17302736 Microbiology Review

Review #1: General Microbiology 1 Difference between Eukaryote/Prokaryote

Eukaryote + Prokaryote:

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Light Microscope: Electron Microscope:

 Eukaryote: sexual reproduction - example: Algae, fungi  Prokaryote: asexual division - example: Bacteria - Are organisms - They contain all enzymes required for replication/division - Plus possess the biological equipment necessary for their production of metabolic energy -

Darkfield Illumination:

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Phase-phase microscope:

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Confocal Microscope:

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Auto Radiograph

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Used in bacteriology Examination of un/stained smears Detailed structure of pro/eukaryotic observed 2 Types: TEM/SEM TEM: Good for minute particles/viruses SEM: Good for 3-D images of surface of micro.org by use of shadowing technique or freeze-drying specimens Performed on dark microscope Creating a darkfield contrasting against the highlighted edge of specimen Used of observing spirochetes Ex: Treponnema pallidum Different phases are converted into different intensities so that some structures appear darker than others Killed and stained org must be used Laser light beams Provide 3-D image from thick fluorescent specimen Useful in cell biology Radio active atom cells fixed on a slide Converts w/photographic emulsion therefore tracks appear in a developed film Useful in following replication of DNA using Tritum labeled thymidine as tracer In Situ hybridization Employes labeled nucleic acid probes used to detect presence viral, bacterial + funcgi nucleic acid in cells/tissues

Difference between Gram (+)ve and Gram (-)ve cells: Gram (+)ve Gram (-)ve • Teichoic acid • Outer membrane containing LPS • Thick • Thin • Peptidoglycan • Peptidoglycan • Blue Gram stain • Red Gram stain • Endotoxin symptoms (fever, shock) Nature of Gram simple stain 1. Cells stained w/crystal violet 2. Treated w/Gram’s iodine  bacteria classified on basis of staining 3. Decolorization w/acetone or alcohol reaction 4. Counter-stain w/safranine or diluted carbolfuchsin  stain allows clinician to determine whether org is round or rod-shaped

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Acid Fasting Stains

Acid fastness inability to stain due to:

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What gives bacteria their shape and provides rigid support:

Type of polysaccharide capsule helpful in serological typing of bacteria and determinant to virulence: Capsule in all gram (-)ve except: Function of a capsule:

Lysosome Enzyme:

Lipopolysaccharide (LPS):

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Aka: Ziell Neelsen Staining Used in bacteria that resist decolorization with acid or alcohol after being stained with strong carbol fuschin - therefore resulting in their inability to stain High concentration of Lipids called: • Mycolic acids granules (Lipid-A) (metachromatic granules) • • • •

Peptidoglycan layer in cell wall Not in human cells therefore Good target for anti-bacterial drugs Eg: Penicllin, Cephalosporin inhibiting cell wall synthesis Polymerized D-glutamic acid -

• • • • • •

•

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Provides specific adherence Present in human tears, mucus, saliva Can cleave peptidoglycan backbone Contributes to natural resistance of host to microbial infection Consist of Lipid-A complex lipids Endotoxin of gram (-)ve bacteria firmly bound to cell surface Released only when cell lysed Target for antibiotics and pyrogenic activity (Fever induction) Found in outer membrane of gram (-)ve bac

Purified form of Endotoxin

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Flagella:

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Mainly in gram (-)ve

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Found in UTI

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For serological classification:

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Pili:

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Anthrax Bacillus Capsule protects organism from environmental hazards Serves as antiphagocytic surface

Spore forming organisms: Spores are:

Organ of locomotion/motility H-antigen Major function: mediate adherence of bacteria to to other bacteria/cells Flagellar proteins used are called H-antigen Flagellar are organs of motility Flagella cell wall = O-antigen Capsular called = K-antigen aka: Fimbriae found mainly in Gram (-)ve 2 Types: Ordinary pili & Sex pili Function: Adhesion

Clostridium, Bacillus (Both Gram (+)ve ) - Clostridium (anaerobic), Bacilllus (aerobic) - Single internal spore produced under unfavorable conditions such as nutrition depletion)

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Mechanism of gene transfer  Conjugation

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Resistant to cold, heat, dyring, chemical agents possess multiplayer protective coating

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requires cell to cell contact plasmids are transferred bacterial conjugation requires F-factor F-factor (Fertility) Phage mediated (infected bacteria) Virulent phage (assemble/release new viruses) Temperature phage (may enter productive cycle or enter bacteria DNA and reside there) Do not require lysogeny and any gene may be transferred by infecting bacterial DNA Requires lysogeny Only bacterial genes next to insertional site are transferred Uptake of donor DNA by recipient cells Most primitive mode of gene transfer Donor DNA that does not carry info needed for its own replication must recombine w/recipient DNA to become established New properties are conferred on bacterial cell by products of prophage genes

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 Transduction

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2 Types: 1) Generalized Transduction 2) Specialized Transduction

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 Transformation:

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 Recombination

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Lysogenic conversion

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Antimicrobial Chemotherapy

1. By inhibition of cell wall synthesis

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2. -

3. -

4. Bacterial Plasmids:

For most antibiotics:

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Methods of Sterilization:

Penicillin, Bacitracin, Vancomycin By inhibition of cell membrane function Amphotreicin-B By inhibition of protein synthesis Chloramphenicol, Tetracycline By inhibition of nucleic acid synthesis Quinolones, Rifampin, Cirpo carry genes for antibiotic resistance carry genes for synthesis of pilli and genes that code for exotoxins genes essential for growth of host cells are NOT carried Susceptibility + resistant break points based on level of drug in serum/blood Not in urine or other fluids

Physical agents - Dry heat (oven: 160 degee celcius) - Moist heat (autoclave: 121 degree celcius) - Radiation (UV light) - Filteration (candles, asbestos pads) - Ultrasonic vibrations Chemical agents - Alcohol (70% concentration) - Phenol - Heavy metal ions - Oxidizing agents - Detergents (soaps)

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In Vitro (outside the body) anti-septic/antibiotic susceptibility testing depends on:

Review #2: Immunology 1 Immunity defn: Types of immunity:

Measurement of immunity: Immune Response:

Immunogenicity deponds on: Immune reponse altered by: 2

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Resistence by the host towards injury caused by micro.org and/or products • Acquired – adaptive • Passive – natural • Local – destruction at local level • Herd – control of disease in body - Agglutination, Precipitation, Complement fixation - Testing level of antibodies  Primary, Secondary  Humoral (Antibody mediated) response  Cellular (Cell mediated) response - foreigness, chemical nature/size - amount of immunogen, time of exposure, mode of administration and duration of exposure

Antigen / Antibody:

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Antibodies:

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Classes of Immunoglobulins: IgG IgM

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IgA

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IgD

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IgE Abnormal immunoglobulins 3

Auto-immune diseases:

Type of medium used Quantity of organism (inoculum) Incubation period

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response depends on: • dose, route, timing, administration Ab are produced in response to Ag Abs are immunoglobulins Secondary response Crosses placenta Mainly in internal secretions (blood, CSF) Primary response Presence in fetus  intrauterine infection Secretory immunoglobulin Present in external secretions • Tears, saliva, sweat, breast milk, GI secretions, Mucous secretion of respiratory tract, Urogenital tract Present in traces only Found on surface of B lymphocyte Marker for B mature cells Allergic / antiparasitic responses Cryoglubulins, Bence Jones proteins

 Chronic thyroiditis + Grave’s Disease

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Immune deficiencies:

Location of cells: • B-cells:

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T-cell: Cells that attack (protozons): 4

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 Hemolytic anemia  Thrombocytopenia & granulocytopenia  Abnormal immune response  Could be congenital or acquired • B-cell (Ab) – recurrent infections • T-cell – Acquired immuno def syndrome follicles  funtn: markers of foreign pathogen paracortex  funtn: defense against intracellular patho CD4 T-cells

Activation cells: o B-cells o T-cells o Macrophages o NK cells o ABO-incompatibility o Rh blood group Class I antigen: (HLA-A/B/C) Class II antigen: (HLA-D) Transplant success requirements:

Transplant donors 6

 IL-1  C3  gamma-interferon from T-cells  Type II hypersensitivity rxns (kill tumor cells)  Transplant rejection/Type II hypersensitivity  only RBC’s CD8 cytotoxic T-cells recognized these antigens CD4 helper T-cells & macrophage recognize these • ABO blood group compatibility • Absence of anti-HLA cytotoxic Abs in recip. • Close matches for HLA-A/B/D bet/n donor/recipient Siblings are best donors sources

Graft types: o Autograft o Isograft o Allograft o Xenograft Corneal transplant:

Transfer of tissue from self-self, best survival  Between identical twins  Between unrelated individuals  Between one species to another (pig vavles) Best overall allograft survival rate

Complement fixation rxn: Testing of complement system: ~Classical pathway ~Alternative pathway

~Hemolysis test: (-)ve  Presence of bacteria (+)ve  No presence of bacteria C3 is the 1st step in complement system Low C4 or C2 is activated Low factor B if activated

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Latex agglutination rxn:

Antibody to capsular antigen is attached to beads

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Examples of hypersensitivit Rxns: Type-I

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Type-II Type-III Type-IV (delayed type) 10

In acute inflammation: Patients deficient in C8 have increased incidence:

Eczema, hives, asthma, hypersensitivity to bee sting (involves: IgE)(eryth. Lesions w/in 30min) Goodpasture’s syndrome, Myasthenia gravis - Cells coated by specific IgG/IgE Abs are destroyed by cells (eg: NK/esoinphils) Serum sickness, SLE - Circulating immunocomplexs, IgG/IgM deposit in target tissue activate complement system Poison ivy, nickel(metal) contact, soap, tuberculin, dermatitis - Skin test needs to be performed Accumulation of polymorh nuclear cells (PML) Meningitis due to Neisseria

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Inability to response to self-antigen HLA-27 is a risk factor for Review #3/4: Bacteriology Staphylococcus

Aka: Tolerance Ankylosing spondylitis arthritis -

 Acute endocarditis  Abscesses  Post-op wound infect.  Toxic shock syndrome --------------------------------- Catheter-prosthetic device infections

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 Exotoxin: Coagulase (+),Entertoxin

-------------------------------- UTI in young women

Enterotoxins

Coagulase Hemolysis

Gram (+)ve spherical cells Arranged in grape-like-clusters (pigmented colonies) Normal flora: Skin, mucous membranes Manifestations: abscess, septicemia, pneumonia in lungs/liver Stains: Hemolysis of RBC on blood agar Catalase (+)ve – all staph Coagulase (-)ve…except staph. aureus Types: • Staph. Aureus

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 Beta-hemolysis  Enterotoxin caused food poisoning • Staph. Epidermis  Coagulase (-)  No hemolysis  Susceptible to novobiocin  Catheter-prosthetic device infections • Staph. Saprophyticus  Coagulase (-)  No hemolysis  Resistant to novobiocin Tx: Penicillin Hospitals have higher risks of carrying antibiotic resistant staph. Cause food poisoning Heat stable toxins Resistant to gut enzymes S/S: Nausea/vomitting, ab-pain, diarrhea Best correlate of pathogenicity Coverts fibrinogen to fibrin (clot) Allow org to adhere Alpha  partial breakdown of RBC Beta  complete breakdown of RBC Gamma  no breakdown of RBC

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Pneumococci can be typed by:

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The coagulase test, in which the bacteria causes plasma to clot is used to distinguish Each of the following concerning staph. Aureas is correct except: Staph. which is part of normal floral of human skin:

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Swelling of the capsule in the presence of type specific antiserum Staph. Aureas from Staph. Epidermis Treatment should include Beta-Lactamase resistant Penicillin S. Albus

Streptococcous

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Gram (+)ve cocci, Catalase (+) Types: Group A, B, D, S.Viridens, S. Pneumoniae

Group A

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Capsule of group A strep have • Hair-like pill that consist of protein-M and lipoteichoic acid that aid in attachment to epithelial cells

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Aka Strep. Pyogenes • Catalase (-), Beta-hemolytic • Remain in throat/skin causing sore throat Streptolysin .O: - Subsurface blood agar - Hemolysis in anaerobic conditions Strep. S: - Responsible for beta-hemolysis Streptokinase - Fibrinolysin (plasmaplasminogen) - Associated with virulence - IV tx of pulmonary emboli/thromb. Streptodornase - Liquefaction of pus Hyaloronidase - Halornic acid - Hydrolyses ground substance of connective tissue therefore helps spread infection - Causes fever - Produce rash of scarlet fever - Inhibit liver clearance therefore creating shock - Onset of fever, sore throat, malaise, headache, nasopharyngitis, tonsilar abscess - All may spread to middle ear, mastoid meninges Local infection of superficial layer of skin (IMPEDIGO) Strep may settle on normal or previously deformed heart valves producing endocarditis - Involves abnormal vales (congenital deformities, rheumatic fever, artherosclerotic lesions) - Transient bacteriaemia when Strep accidentally reaches blood (usually seen after dental extractions) - In these case, prophylactic treatment is used - Rheumatic fever, Glomerulo-nephritis - Latent period of 1-4 weeks due to hypersensitivity response - Develops 3 weeks after strep infection - Nephritogenic stains involves basement membrane - Blood/protein in urine - W/edema, hypertension, urea/nitrogen retension - Damage to heart muscles/valves - S/s: fever, malaise, evidence of all parts of heart inflamed (endo/myo/pericardium) leading to thickness of valves (deformities) - Tx: Prophylactic penicillin prevents pharyngitis - Gram (+), Catalase (-), Beta-hemolytic - In vagina - Dz: Neonatal meningitis/septicemia - Pathogenesis: ~(+) cAMP test ~Infection assoc/w/ premature rupture of membrane - Gram (+), Catalase (-), Enterococcus, variable hemolysis - Transmission: during medical procedures (GI/Ug) in blood stream onto previous damaged heart valves causing endocarditis - In colon, urethra, female genitals - Lab: grows with 6.5 NaCl (& in presence of bile) - Dz: Urinary/biliary tract infections, endocarditis w/damaged heart valves - Tx: problems with drug resistance -

Toxins – produced by group A

Strep Exotoxin A-C Sore Throat C/F: Dz: Strep. Pyoderma Infective Endocarditis Sub-acute endocarditis

Post Strep. A Acute Glomerulonephritis

Rheumatic fever

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Group B – Strep. Agalactie

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Group D: Strep. Faecalis (Enterococcous)

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Viridans Streptococci - no group - S. Sanguis, S. mutans

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Strep. Pneumoniae - no group

Toxin of Strep.pneum.

Q Q Q Q Q Q

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Gram (+), Catalase (-), alpha hemolysis In oropharynx Spread by dental work, poor dental hygiene into blood and damaged heart valves - Dz: Sub-acute bacterial endocarditis, dental carries - Prevention: Prophylactic penicillin - Gram (+), Catalase (-), Lancet-shaped cocci - Transmission via: resp. droplets - Pathogenesis: IgA  helps in colonization Teichoic acid  present for attachment Polysaccharide cap.  virulence factor - In upper respiratory tract (dz is caused in lower resp) - Lab: - (+) Quellung Rxn (Swelling of capsule in presence of antiserum leading to pneumonia) - Inhibited by optochin - lysed by bile Pneumolysin O - similar to Strep. O – released by - when reaches alveoli (lower resp) capsule - damages cells w/cholesterol - damages resp. epithelium - inhibits leukocutes and complement fixation - outpouring of fluid, RBC, WBC causing CNS inflammation Dz: Bacterial pneumonia, adult meningitis, Otitis media & sinusitis in children -

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The principle toxin of Strep. Association with virulence is: Acute glomerulonephritis is associated with: Which organism causes subacute bacterial endocarditis: Pneumococci differentiated from Step. Viridans is by: Subacute bacterial endocarditis caused by a member of viridian of Strep. Which one is the source of the organism in the this infection: A culture of a skin lesion from a patient with pyoderma (impetigo) shows numerous colonies surrounded by zone of beta-hemolysis on blood agar. A gram stain smear shows gram (+)ve cocci. If you catalase test (-)ve, which of the following organism is to be isolated: What is the most common infection due to Beta-hemolytic strep.: 45-yr-old male w/alcohol abuse, periodontal disease, fever/chills, pneumonia with lung consolidation. CXR shows cavity in right lower lung; what type of bacteria involved: Neisseria

Streptokinase Strep. Pyogenes Alpha-hemolytic strep (Strep. Viridans) Bile solubility Oropharynx Step. Pyogenes

Strep. Sore throat Anaerobic bacteria b/c organism is elsewhere + causing disease elsewhere (mixed infection)

Gram (-)ve cocci occur in pairs Oxidase (+) - Capsule prevents phagocytosis - Endotoxin: produces shock - Non-motile (kidney shapped) - 2 types: N. gonorrhea, N. meningitides - found associated with or inside PMN cells Culture: ~ferment carbohydrates producing acids only ~requires 5-10% CO2 -

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N. Gonorrhea - STD

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E.Coli

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Ferment GLUCOSE only Have pili (attachment/resist phagocytosis) IgA protease hydrolyzes secretory IgA for adherence Protein I – extends thru cell membrane Protein II – functions in adhesion and attachment LOS – toxicity in infection due to endotoxic effects Chocolate agar Dz: - Attack: mucous membrane of genitor-urinary tract, eye, rectum, throat with tissue invasion followed by inflammation and fibrosis • Males – urethritis with yellow creamy pus and painful urination • Females – infection in endocervix extending to cervix and vagina with mucopurulent discharge Gonococcal bacteriaemia - Leads to skin lesions, hemorrhagic, pustules - On hands, forearms, feet, legs, supportive arthritis in knee, ankle and wrists Gonaococcal ophthalmia - Infection of eye of newborn - Acquired during passage thru an infected birth canal - If untreated may lead to blindness N. Meningitis - Ferments glucose AND maltose - Nasopharynx port of entry & may reach bloodstream producing bacteriaemia causing pharyngitis - Pathogenesis: ~ Polysaccharide capsule ~ IgA protease allows colonization ~ Endotoxin ~ Pili and outer membrane protein II for virulence - Lab: Latex agglutination (beads) Which doesn’t influence virulence of N. gonorrhea: Genus specific protein Neisseria are all: Oxidase (+)ve Effective vaccines presently in use against meningococceal Capsular polysaccharide disease contains which as primary immunogenic agent: Neisseria meningitis: Differs from other species of neisseria by family of various sugars, oxidase (+)ve, grows in 5-10% CO2, prosses endotoxin N. gonorrhea: Has pilli if pathogenic, produces penicillin, is oxidase (+)ve, grows best under 10% CO2, may cause blindness in newborns + stertility in women Frequent bacteria responsible for pharyngitis: Neisseria meningitis Organism most likely to cause conjunctivitis/eye infection in N. gonorrhea new born if appropriate preventative measures are not taken: -

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UTI

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Lactose fermenter Reservoir: Colon, colonizing vagina/urethra (urogenital epithelium) Normal flora: Intestine Hospital acquired infection Tx: Ampicillin, Cephalosporins, Rehydration Prevention: ~Limit use of urinary catheter ~Eat only hot cooked food, drink only boiled water/beverages in risk countries Imp. For sampling water Many Clinical features: Urinary Tract Infection, Biliary tract infection C/F: Urinary frequency, dysuria, hematuria

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EPEC (Enteropathogenic)  some form of diarrhea ETEC (Enterotoxigenic)

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Watery diarrhea in infants in developing countries

- Traveller’s diarrhea - Heat Labile: Stimulates cAMP - Heat Stable: stimulates guanylate cyclase, fimbriae - Severe diarrhea results in acute renal failure - Invade human epi cells and cause diarrhea - Causes acute/chronic diarrhea in develop.countries - E.coli reaches blood stream and causes sepsis - Newborns susceptible b/c lack IgM Abs - May occur secondary to sepsis - in infants

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EHEC (Enterohemorrhagic) EIEC (Enteroinvasive) EAEC (Enteroaggressive) SEPSIS

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Meningitis

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Organism commonly characterized by its O, K, H antigen + ability to ferment lactose: Organism most likely responsible for UTI: In the intestinal tract the organism that is lactose fermenting is:

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Klebsiella pneumoniae

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Gram (-), non-motile Lactose-fermenter

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Reservoir: Resp. tract & feces

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Causes: Bacterial pneumonia, UTI, Bacteremia; Hospital acquired infection Dz: Upper lobe cavitation with thick mucous Associated with: Alcoholics Capsule: impedes phagocytosis Endotoxin: Causes fever, shock assoc/w/septicemia No exotoxin Not susceptible to Penicillin

Klebsiella p. has the following features except: Proteus

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Shigella

E.Coli E.coli

• •

• • • • Tx:

E.Coli

Susceptible to penicillin

Gram (-), Motile (flagella) Urease (+) / H-antigen (+) Produce infection in UTI only when bacteria leaves intestinal tract S/s: bacteriaemia, pneumonia, UTI, diarrhea Lad: smear not useful but PPA test (+)

Gram (-) rod, Non-lactose fermenting, non-motile Normal Flora: Intestine (Ileum, Colon) Transmission: Fecal/oral spread, person-to-person & Fingers, food, feces, flies - Pathogenesis: Infection limited to intestinal tract b/c no blood stream invasion - Endotoxin: irritation to bowel wall - Exotoxin: Type-1: affects gut/CNS; also inhibits sugar and amino acid absorption in SI - Enterotoxin: Diarrhea - Neurotoxin: fatal nature of Sh. Dysenteriae in CNS C/F: Fever, watery diarrhea, malena, dehydration, acidosis - Most servere disease - Most common in USA - Infection in intestine -

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Sh. Dysentriae Sh. Sonnei Bacillary dysentery

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Exotoxin that function as a neurotoxin and enterotoxin Which species of Shigella is responsbible for basically dysentery in the US: Salmonella

Sal. Typhi (D) Enteric Fever (Typhoid)

Enterocolitis (gastroenteritis) S. paratyphi Q Q Q Q Q Q Q

Gram (-) bacilli, Motile H-antigen (+) - Transmission: Oral route, animal/animal products - Causes: Enteritis, systemic infection, Enteric fever - Produces: H2S which produces black stool - Carrier: Gall Bladder, biliary tract - Antigenic structure includes: Capsular K-antigen but is referred to as Vi- antigen which may interfere with agglutination - Lab: Triple Sugar Iron agar, Rapid slide agglutination, Widal test, Tube agglutination - Tx: Multiple-drug resistant - Source of Infection: ~Food/drink (Water/Milk/Cheese) ~Meat/products/eggs - Most important classification type • reaches SI then lymphatics then blood stream to organs, including intestine then multiply in intestine and finally excreted in stool • Incubation period: 10-14 days • Peyer’s patches may be seen due to necrosis C/F: Nausea/headache, vomiting, perfuse diarrhea Most common casue of non-typhoid fever and cause of osteomyelitis in pts with sickle cell disease -

Salmonella food poisoning: Early in course of Typhoid fever, Salmonella typhi is isolated from: Which of the following Typhoid antigens is to be most immunogenic: Outbreak of Typhoid fever occurred in a local high school due to: Which organism produces disease resembling Salmonellosis: Salmonella & Shigella are differentiated in the lab by: 6-wk-old infant with 10 days cough/choking; WBC –20% lymphocytes, vomits x2, encapsulated gram (-) ve rods on which media:

Pseudomonas

Shigella dysentriae S. Sonnei

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S. Typhimurium Blood V1 Cook in school cafeteria Campylobcter jejuni Motility Triple sugar iron agar or Urease agar

Gram (-) rods, aerobic, Motile Oxidase (+) / H-antigen (+) Produce pigment Tx: Multi-drug resistant

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P. aeroginosa

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Fruity odor with greenish-blue color pus (pyocyanin) Have pili Commonly seen in infant patients with cystic fibrosis, wounds, burns, lumbar puncture, endotracheal tube Most common cause of death with cystic fibrosis pts Exotoxin produced when mucus membrane/skin disrupted (as in when urinary catheters are used) b/c it inhibits protein synthesis (similar to diphtheria toxin) Endotoxin: causes inflammation, shock w/septicemia

Organism most common bacterial pathogen to complilcate (+)ve management of patients with cystic fibrosis:

P. aeruginosa

Acinetobacter

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Gram (-), aerobic Found in soil/water/skin/mucous membrane Appearance like Neisseria but Oxidase (-)

Actinomyces

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Actonomyces, anaerobe Sulphur granules Draining sinus tracts in jaw, throat, abdomen Yellow flecks of material in drainage fluid

Virbrio

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Gram (-) rods, motile (polar flagellum=very mobile) H-antigen (+) / LPS Capsule (O-antigen) Found in surface water Enterotoxin (heat labile)  watery diarrhea Oxidase (+) Dz: Cholera Culture: ~Grows on selective medium (TCBS) ~Grows at high alkaline pH (8.5-9.5) Pathogenesis: Killed in acidic mediums, does not reach blood stream C/F: Rice-water-stool Tx: Tetracycline

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Vibrio cholera needs:

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Cholera enterotoxin Campylobacter  C. Jejuni  C. Coli

Marked tolerance for alkaline pH grows at high Ph 8.5-9.5 All

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C.Jejuni Enterotoxin

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Gram (-), comma (S) shaped rods, Motile H-antigen (+) Oxidase (+) / Catalase (+) Non-fermenters Similar to Neiserria due to Co2 requirement Common cause of bacterial enteritis (invasive) Due ingestion of contaminated poultry, milk, water causing decreased gastric acidity, increasing chance of infection Culture: grows at 42 degree cent. Reservoir: Human feces Transmission: Fecal/oral, chicken Tx: Erythromycin Similar to Salmonella Ulcerative colitis (w/malena) & pseudomembranous colitis Similar to Cholera

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Helicobacter

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Yersenia

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Y.Peptis Y.Pseudotuberculosis Y.enterocolitis

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Pasturella

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Haemophilus (“blood loving”)

H. Influenzae B H. ducreyi H. Influenzae A-F Dz: Secondary Dz: Q

Gram (-) spiral shaped Multiple flagella  H-antigen (+) Oxidase (+), Catalase (+), Urease (+) Culture: Grows at neutral pH Associated with gastritis, duodenal (peptic) ulcers/carcinoma, gastrointestinal lymphomas arising from MALT in stomach Found deep in mucus layer near epithelial surface Pathogenesis: Produces protease modifying gastric mucosa (causing ulcer) which requires biopsy for diagnosis Lab: Detect urease activity Tx; Triple Therapy for 14 days Gram (-), short, safety-pin appearance Catalase (+), Oxidase (+) Endotoxin: ~Bubonic plague by bite ~ Lymph node enlargement ~ Primary pneumonic plague Transmission: Inhalation of droplets causing sepsis/death S/S: Lymphadenopathy, high fever, hypotension, renal failure Produces plague (black death) Respiratory pneumonia Contaminates blood during transfusion Triggers ankylosing spondylitis Diarrheal disease Gram (-), small rods Reservoir: Mouths of animals (cats/dogs) Transmission: By bites Diagnosis: Wound infection – Cellulitis w/lymphadenitis Exotoxin: Capsule spreading within skin rapidly Tx: Amoxicillin

Gram (-) coccobacillus - Capsule: Virulent factor - Exotoxin: none - Normal Flora: Upper respiratory tract w/possible extension into middle ear and sinuses - Transmission: Respiratory tract (person-to-person) especially in children (5mo –5 yr) - Lab: Isolated by blood - S/s: Inspiratory stridor, lateral neck x-ray revelas thumbprint - Culture: ~Brain heart infusion agar w/blood ~Growth requires X(blood)+V(NAD) factor - Immunization  Capsular vaccine Common cold (most virulent of all) -STD (Chancroid) w/ Ulcers on genitalia, inflame/tenderness -Diff/Diag: Syphilus, Herpes Simplex Flu Meningitis (very common among children and if left untx  may be fatal), Pneumonia, Empyema, Epiglottitis, Cellulitis Chronic bronchitis, otitis media, sinusitis -

4-yr-old with respiratory distress with 103.8oF fever; drools, difficulty swallowing, stridor. CXR shows epiglottis swelling. Infant has never had a vaccine:

H. Influenzae

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Bodetella B. Pertusis  Whooping cough disease

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Gram (-), non-motile Morphology: Resembles H. Influenzae Capsule: present Lab: Blood isolation Exotoxin: Irritate surface cells producing cough/ lymphocytosis Transmission: Respiratory route (person-to-person) Pathogenesis: Adhere/multiply on epi-surface of trachea, bronchi and interfere with ciliary axn Dz: Untx leads to necrosis of epithelium with PMN infiltration and peribronchial inflammation therefore resulting in interstitial pneumonia Secondary Dz: Bact. Pneumonia with atelectasis and decreased O2 in blood leading to tertiary dz of convulsions in infants Immunization: DPT containing killed bordetella bact.

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Mild coughing/sneezing Shed large # of org Not very ill Incubation: 1-2 weeks

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Exploxive coughing w/ “Whoop” upon inhalation Rapid exhaustion w/vomiting, cyanosis, convulsions Incubation: 2-4 weeks

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Different Stages  Catarrhal:

 Paroxsymal

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ADP-ribosyl transferase which effects G-regulatory protein causes increase cAMP levels: Paroxysms of cough known as Whooping cough which organism involved: • •

Brucella

Pertussis toxin Bordatella pertussis

Gram (-), Oxidase (+), Urease (+) Typically infest animals

•

B. melintensis  Brucellosis  Infects goat

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 B. arbortus

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S/S: Malaise, fever, weakness, aches, sweats, GI & Nervous symptoms, lymphadenopathy • Acute infection leading to chronic Serology: 1st week increased IgM 4th week increased IgG Fever, acute bacteriaemia, non-motile, gram (-) Isolation in blood Transmission: ~Intestinal tract (infected milk/products) ~Mucous membrane ~Skin (contact w/inf animals Spreads via lymphatic channel, thoracic duct, blood stream Dz: affects paraenchymal organs leading to abscess in liver/spleen/bone marrow Secondary: Osteomyelitis, meningitis, cholecystitis Increased Co2 for growth Mild dz Non caseating granuloma In pregnant animals, infection reaches placenta causing: Placentitis & Abortion However not in humans

16-yr-old girl with enlarged lymph node (Right axilla). Blood count – normal; Granulomas w/neutrophils + necrotic debris. Which org:

Brucella Henselae (also responsible for cat scratch disease) (??bartonella)

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Legionella  Water loving pathogen

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-

Q

Gram (-) long rods Catalase (+), Oxidase (+) Normal flora: Sputum Culture: Yeast agar (fails to grow on ordinary media must be supplemented with iron and cysteine (Silver stain), slow growing org. Seen best with immunofluorescence Transmission: Inhalation of aerosols generated from air conditioner, shower heads Dz: ~Outbreak of pneumonia (pneumophilia) ~Lobular, segmental, patchy pulmon.infiltrations Incidence: ~Higher risk in males > 55 yr ~Smokers, Diabetics, Pts w/chronic bronchitis, transplant pts or immunosupp. S/s: Fever, chills, malaise, non-prod-cough, hypoxia, diarrhea, delirium, leukocytosis, hyponatremia, hematuria, bronchopneumonia Lab: Isolation by bronchial washings since it is difficult with sputum/smears

Alcoholic + smoker, dyspnea, headache, muscle pain, fever, chills; which organism involved: Gardenella Vaginalis

-

Legionella pneumophillia

-

Dz: Vaginosis (non-specific / bacterial vaginitis) Pathogenesis: Clue cells yielded with absence of common causes of vaginitis (eg: yeast, trichomonas) Lab: Vaginal discharge will have “fishy odor” containing anaerobes and pH will be > 4.5 Tx: Metronidazole

Calymmatobacterium  aka Donovania

-

Related to Klebsiella Causes: Granuloma Inguinale Rare STD of genital ulcers

Whipples Disease Tropheryma Whippelli

-

S/s: Fever, pain of abdomen, diarrhea, wt.loss, polyarthritis Gram (+)

-

Corynebacterium  Diphtheria

-

-

Gram (+)ve club-shaped rod, aerobic, non-filamentous Exotoxin produced T: resp. droplets Manifestation  sore throats, resp. infections C/F: Lymphadenopathy/edema of entire neck, difficulty swallowing Path: • pseudomembrane (gray) formed over tonsils, pharynx, larynx

15

Q Q

• Inhibits protein synthesis by ADP-ribosylation of EF2 - Stain: blood samples will not be helpful b/c it does not enter bloodstream - Virulence test: Eleks test - Prevention: w/toxoid (active) immunization DPT - Tx: Pencillin, Erythromycin (inhibits growth of bacteria) Corynebacterium diphtheria: Child should be given toxoid All are correct about corneybacteria except: C. Diptheria toxoid shouldn’t be given to kids under 3 years b/c incidence of complication is too high Clostridium

-

C. Tetani C.Botulinum Infant botulism Wound botulism

C.Perfringenes Alpha-toxin of C.p Entertotoxin

-

Cl. difficile

Q Q Q Q Q Q Q Q

-

Gram (+) bacilli, Motile H-antigen (+) with flagella Culture: Grows under anaerobic conditions Reservoir: Found in intestinal tract Transmission: Puncture wounds/trauma (produces tetanus) Extreme muscle spasm Blocks release of inhibitory mediators at spinal synapses Produced in poorly preserved food (canned beans) Symptoms: Weakness, dizziness, blurred vision Muscle paralysis Household dust ingested Causing constipation, limpness diplopia/dysphagia (floppy baby) Toxin produced in gut Traumatic implantation of spores In Vivo production of toxin Tx: Penicillin Blocks release of Ach at myoneural junction in flaccid paralysis Heat labile Non-motile Found in soil, human colon Dz: Gas gangrene (myonecrosis) Disrupts membranes hemolyzing RBC, damaging platelets Causes food poisoning Disruption of ion-transport  watery diarrhea and cramps Pseudomembranous colitis Yellow plaques on colon Production of lecthinase

Causes muscle paralysis: The most important for preventive function of the antibody stimulated by Tetanus: All correct about Clostridium Perferinges except: Which concerning immunization against disease caused by clostridrium is correct: What organism causes gas gangrene: Each is true concerning wound infection caused by perfringens except: Causes muscle spasms: Causes nyonecrosis: Virulence tests

Listeria Monocytogenes  Perinatal human listeriosis  Listeria meningitis

-

Botulinum toxin To neutralize the toxin of the pathogen Gram (-)ve rod that does not ferment lactose Immunization with tetnus toxoid induces effective protection against tetnus C. Perfringes Organism grows only in human cell culture Tetanus toxin Clostridium alpha-toxin

In Vitro  Elk’s test (neutralization test / horse serum) In Vivo  inoculation and observation -

-

Gram (+)ve rod T: Oral – GI tract Eating unpasteruzied cheese (Goat milk’s cheese)

16

Q Q

28 yr-old preg. Women with fever, headache, myalgia, pain and spontaneous abortion: Neonate with widespread granulomas in uterus: Bacillus Anthrax  Woolsorter’s disease

-

Q

Motility: 22o – yes 37o no Manifestation  early intrauterine sepsis/death/meningitis in neonates/adult transplant patients Path: Invades mononuclear cells Stain: Beta-hemolysis in blood agar and CSF culture Tx: Ampicillin

Bacillus Anthrax:

Mycobacteria Many Types M. Tuberculosis

Tuberculin test Atypical Mycobacteria

Listeria monocystogenes Listeria monocystogenes commonly acquired from uterus

Gram (+)ve rod, spore-forming, aerobic Polypeptide capsule of D-glutamic acid Resistant to heat T: Skin/mouth/inhalation Manifestations: Skin ulcers/malignant pus, pneumonia in people working with animal (hides), soil, Tx: Pencillin Prevention: Immunization with live vaccine Causes Woolsorters disease

No gram stain, Rod shaped, aerobic, non-spore Not easily stained and if stained- resist decolorization Therefore: Acid fast bacilli M. Tuberculosis, M. Avium, M. Bovis, M. Leprae, M. Ulcerans, M. Balnei, M. Butyricum, M. Phelei, M. Sterocori and atypical mycobacteria - Catalase (-), Aerobic, Acid Fast bacilli - Cell wall with mycolic acids (increased lipid content) induces delayed hypersensitivity (resistance to inf) - Culture: ~Slow growth (3-6 wks), ~Produces Niacin ~Salt solution required M.tub.Hominis  Respiratory Tuberculosis (most common) M.tub.Bovis  Intestinal - Transmission: Inhalation – reaching alveoli where it fully establishes and proliferates - Lesions: Exudative type • Ac. Inflame.rxn, edema w/fluid, PMN, Peyer’s Patches with obstruction in terminal ileum • (+) Tuberculin test (leads to hypersensitivity and resistence to recurrent episodes) Productive type • Chronic granuloma in Central (multinuc.giant cells), Midzone (Pale epi-cells), Peripheral (Fibroblasts) - Tx: drug resistance common especially in immune.supp pt. - (+)ve test does not prove presence of active dz therefore isolation of organism needed for diagnosis - Non-tuberculosis mycobacteria -

17

Q Q

M.avium, M.kansosii, M.smegmaus, M.scrofulaceum

-

Pulmonary symptoms

-

Opportunistic in nature Slow growth in culture

M.Kanasii (photochromoge), M.Avium - Aids, cancer, chrong lung disease patients (imm.sup) - Disseminated TB in Aids patient Lymphadenitis symp - M.Scrofulaceum - Children affected (painless cervical adenopathy) Gastrointestinal symp - M.Avium - Immunocompromised patients Soft Tissue - M.Ulcerans - Seen in tropical fishing persons Swimming pool granuloma - M.Marinum Rapid Growing - M.Fortuitum AIDS patient with chronic cough, has been running low grade M. Avium Complex fever. CXR is unremarkable. Sputum demonstrates acid fast organisms. CD4 + T-cells 500/mL. Which causative agent: Disfiguring lesions with loss of sensation to touch. Scrapings M. Leprae from skin lesions show which org: Spirochetes

Q Q

- Motile (H-antigen (+)) - Treponema, Borrelia, Leptospira Lyme’s disease - Borrelia burgdorferi - Spirochetes in synovial fluid - S/s: arthritis, inflammation of joints Polyarthritis in knees with cough. Sphirochete shows lyme B. bergdorferi disease which organism involved: Global eradication of lyme disease is unlikely b/c: Can be maintained by tick vector Mycoplasma M.pneumoniae

Q Q Q Q Q

Rickettsia, Chlamydia, Lymphogranuloma Vereneum - Acquired infection contracted in military stations and crowded situations - Dz: produces interstitial pneumonia assoc.w/erthema multiforme and bullous myringitis - Requires sterols Rickettsia - Respiratory pathogen transmitted w/o vector - Transmission: Inhalation by individuals who have an association with the birthing process in sheep, cows, goats or milk industry - Coxiella burnetti (shovel feces of sheep) Chlamydia trachomatis - Infertility in women with scarred fallopian tubes  C.pneumoniae - Contracted when newborn passes thru birth canal - Produces pneumonia w/abrupt onset of tachypnea, wheezing, hyperaeration, eosinophilia and lack of fever, maybe association with coronary artery dz leading to interstitial pneumonia - Transmission: droplets infection - Lab: Cold agglutinins not associated - Tx: Doxycycline C. Trachomatis - Associated with conjunctivitis 19 yr-old pt. w/weakness, malaise, dry cough. 100oF; Mycoplasma pneumoniae bronchial lavage are slow growing. Org: Persistent urethritis: Chlamydia Sexually active femaile experiences lower ab-pain, no rash on Inclusion bodies due to Chalmydia labia; Smear shows scanty neutrophils. What lab results show: Pt. collapses, loss of consciousness, severe lower ab-pain, Chlamydia nausea, shock, ectopic pregnancy. Which organism: 4-yr-old infant with chlamydia trachomonis. Blindness in this Scarring of cornea patient caused by: -

18

Q

Maculopapular rash, shock + renal failure 3 days after returning from camping trip in east USA. Which org responsible for symptoms:

Nocardia

N.asteroids

Review #5: Virology Measles Virus  aka Rubeola

Q Q Q Q Q Q

Q

Gram (-), aerobic Predominantly respiratory pathogen Seen in patients with defects in cellular immunity Ex: Heart transplantation Produces micro abscesses in lung with granulomas Partially acid fast

-

S/s: Child with fever, sore throat & ulcerative lesion on soft palate (Kopliks spots). - From Paramyxovirus family, - Transmission: inhalation - Vaccine preventable 4-yr-old male with fever, sore throat, unusal irritability. P/E shows 10-15 small, gray which shallow ulcerative lesions along posterior margin of soft palate. Pharyngeal walls-red. No lesions on gums. Child is of dark complexion with no obvious rashes. Disease: Measles Lesions found on mouth known as: Koplik’s spots Causative agent: Paramyxovirus Transmission of disease by: Inhalation of droplets Another name for disease: Rubeloa Example of arthropod-bone viruses causing encephalitis in Measles virus humans including all except: Mumps

-

Rabies Virus  Rabdovirus

-

Involves Salivary glands(Parotids) Vaccine preventable

Rod or Bullet shaped Negri bodies diagnostic Virus destroyed by UV radiation - Culture: Multiplies in muscle & conn. Tissue - Infection of the CNS - Incubation 21-60 days.  Isolation by Saliva for rabies virus. Which virus belongs to rhabdovirus group that resembles a Rabies bullet, flat at one end? Infection spread by vector Rabies Inf.prod vesicular lesions Aseptic meningitis Resp. infection Infe in throat or intestine

Q Q Q

-

Rickettsia ricketsii (aka: Rocky mountain spotted fever) due to ticks

Blood Saliva Vessicle fluid CSF Throat swab Throat swab + feces

Rabies source of specimen for virus isolation: Colorado tick fever cultured on: Coxsackie specimen isolated on:

Saliva Blood Throat swab + feces

19

Q Q

Influenzae specimen isolated on: HSV specimen isolvated on:

Throat swab Vessicle fluid

EBV Q

- Nasopharngeal carcinoma - Burkitt’s lymphoma. Burkitts + Nasopharyngeal carcinoma:

EBV

Q

HPV (Papilloma virus) Cervical carcinoma:

HPV

Cervical carcinoma

Herpes Simplex

Q

I  oral lesions (painful) II  genital lesions (painful) Herpes zoster • affects nervous system  aka Shingles • dorsal nerve root of trunk involved A viral org. was isolated from a painful blister on the lip of a Herpes Simples I (HSV) teenager girl. Agent was found to be double-stranded, linear DNA and was enveloped. The patient had similar sore 2 months ago: RSV

Q

-

Cause of pneumonia & bronchiolitis in infants. Only respiratory viruses ****Rota viruses do not cause respiratory viruses

Coxsackie Group B, type 1-6: aseptic meningitis Coxsackie Comm... cause of myocarditis and pericarditis The illness which often results infection w/Poliovirus, Aseptic meningitis Coxsackievirus and Echovirus is: Rhinovirus Rhinovirus Adenovirus

Do not cause gastroenteritis - Common cold in fall and winter - Winters disease - Reservoir is school children. - Transmission: Inhalation droplets Virus responsible for cold in spring and summer.

Live vaccine Q Q

Q Q

-Oral Polio Vaccine (OPV) -Produces lasting intestinal immunity Live vaccine in AIDS MMR Which strategy like to induce lasting intestinal mucosal Oral vaccination w/live vaccine immunity to poliovirus: 9-mo-old infant is brought to health dept. for second dose of Poliovirus OPV (oral polio virus) 2 weeks after 1st vaccine. Child has mild diarrhea and decision is made to defer 2nd dose. Bacterial exam of stool is unremarkable but a small, single strand positive RNA virus is isolated. Same agent in sewage effluent previous week. Viral isolated not affected by either: Varicella Varicella is:

Primary disease of children Primary disease of children

Rotavirus Common cause of diarrhea in children / ELISA for diagnosis 6-months child with persistent cough + fever, physical exam Rotavirus and CXR suggests pneumonia. Which org is lease likely to cause infection: Cytomegalovirus (CMV)

-

Comm. Cause of diarrhea Biliary tract disease & pancereatitis in AIDS

20

S/s: Infant not responding to sound (showing neural deficits) due to periventricular calcification A newborn infant has multiple, hemorrhagic cutaneous lesions Cytomegalovirus (CMV) and does not respond to SOUND. Head CT scan shows periventricular calcification: -

Q

Q

HIV Structure - Multi-shaped but not bullet shaped Structural features of HIV including all Except: Bullet-shaped virion Norwalk Virus

Most comm.. cause of gastroenteritis in adults

HAV

Incubation period of 15-45 days Travelor’s risk; not chronic Transmission via fecal/oral route In vitro + extensive antigenic variation Common in day care centers, jail, corrective centers • Hepatocellular carcinoma (chronic disease) • Polyarteritis nodosa patients affected • Transmission via accidental needle stick - Hepatocellular carcinoma - Post-transfusion, chronic hepatitis - Person-to-person contact - No protective antibodies - Associated with cryoglobulins & membranoproliferative glomerulonephritis • Super infection in patients with active HBV • HbsAg therefore chronic disease • No protective antibodies - No chronic state - Contamination - Transmission: fecal/oral route HCV, HGV

HBV

HCV  Flavi virus

HDV

HEV Flavi-virus Q Q Q Q Q

Q Q Q Q Q

-

The only hepatitis virus that can be grown In vitro is: Transmission is primarily by the fecal-oral route: Infected individuals do not become carriers: Male gender and early infancy are risk factors for chronic infection: Patient with jaundice. P/E reveals nodular, enlarged liver. CT of ab shows cirrhotic liver w/large mass. Ct-guided biopsy reveals malignant tumor derived from hepatic parenchymal cells: Hepatocellular carcinoma: Which hepatitis virus belongs to FLAVI virus group: Most infected persons become carriers: Autonomous replication as well as transmission from patient to patient can be accomplished by all Hepatitis viruses except: Transmission of this virus also have an active HBV infection:

HAV HAV HAV HBV HBV

HBV/HCV HCV HCV HDV HDV

arborV type of encephalitis

Altered mental status, headache. Mosquito-infested swamp, gram stain & culture of CFS is –ve.

Viruses

DNA or RNA  never both

Paroviruses

Erythroid cell replication

21

Q

Child w/sickle cell anemia/ She has been tired lately and may have come down w/virus. She is very pale and severely anemic. Bone marrow aspirate contains no erythroid precursor cells: Virus measurement Cultivation of virus

ECLIPSE period Mode of Transmission Person to person Fecal/oral route Arthropod vecor HIV, CMV, HBV, Rubella

Parvovirus

Electron microscopy - Fertile eggs (chick embryo) - Results in death of embryo - Production of pocks/plaques - Chorio-allantoic membrane involved - Viral replication after interaction with host, phase of growth cycle  Influenza, measles, pox  Rotavirus, Hep. A  Arbovirus All have increased congenital risk factors

Review #6: Parasitology A Protozoa - ingest solid pieces of food thru a small mouth called the cytostome - reproduce asexually; undergo DNA replicat’n - when exposed to new environments; such as temperature changes, transit down the intestinal tract or chemical agents… they secrete a protective coat and shrink into a round armored form called cyst - It is this cyst form that is infective when ingested by humans - Following ingestion it converts back into motile form called trophozoite  Avoid contaminated food and drink B Intestinal protozoa - 5 that cause diarrhea • Entamoeba histolytica causes a bloody diarrhea • Giardia lamblia & Cyclospora cayetanensis cause a non-bloody diarrhea • Cryptosporidium & Isospora belli cause severe diarrhea in individuals w/defective immune systems (such as AIDS) C

D

Free-living meningitis-causing amoebas - Naegleria fowleri and Acanthameoba - Live in fresh water and moist soils - Infection common during summer months when people swim in pools and lakes - Although large exposure, infection is rare - When It does occur, organisms penetrate nasal mucosa thru cribriform plate into brain and spinal fluid causing meningoencephalitis Infection in AIDS patients - Cryptosporidium and Isospora cause severe, chronic diarrhea - Toxoplasma gondii and Pneumocystis carinii - Ineffective immune system sets them up for certain infections that seldom affect immunocompetent patients

22

1 C/F

Entamoeba histolytica – aka: Amoeba - Asymptomatic carriage Intestinal amebiasis (acute or chronic) - Bloody diarrhea when trophozoites invade intestinal mucosa causing erosions - Abdominal pain, cramps Extra-intestinal amebiasis - Liver abscesses followed by spread thru diaphragm into lung - Further causing pulmonary abscesses and often death Dx - Fecal (stool) exam  for cysts & trophozoites w/RBCs w/in cytoplasm - Sigmoidoscopy - Abdominal CT  for liver abscesses Tx - Metrondiazole Morphology • Oocyst (pseudohyphae) n’ stuff • Trophozoite: motile + ingests RBCs in cytoplasm • Homosexual men commonly are asymptomatic carriers Q 27 yr IV drug user, diff swallowing. White plagues along  budding yeast – pseudohyphae tongue and oral mucosa Q Entamoeba histolytica can cause: Abscess in the liver and lungs 2 C/F

Giardia lamblia - Foul smelling, greasy diarrhea ( ↑ fat content ) Steatorrhea - Abdominal gassy distention - Duodenum/jejunum involvement b/c parasite adheres to lining interfering intestinal fat absorption - Does not invade intestinal wall (only adheres) therefore no blood in stool Dx - Fecal (stool) exam  for cysts & trophozoites - Immunoassay to detect for org in stool Tx - Metrondiazole Morphology • Oocyst • Trophozoite: flagellated 3 Cyclospora cayetanesis C/F - Watery diarrhea + Nausea/vomiting Dx - Stool exam  for oocysts that fluoresce under UV light Tx - Trimethoprim/sulfamethoxazole Morphology • Oocyst n’ stuff  Oocysts from stool contaminate fruit/vegetables 4 C/F

Cryptospoidium - Watery diarrhea + vomiting + abdominal pain (no blood) - Involves: brush border of small intestine - ↑ incidence in AIDS pt: > 50 stools/day, ↑ fluid loss (up to 3-17 liters of stool/day) Dx - Fecal exam  for oocysts - Biopsy  small intestine lining - ELISA for detection of Antigen Tx - Usually self-limiting  No effective therapy Morphology • Oocysts is infective agent ( contains 4 sporozoites) n’ stuff • Life cycle occurs w/in epithelial cells • Animals and humans are equally infected • Outbreaks of diarrhea from contaminated water sources and infants in daycare centers • Sporadic cases in travelers 5

Trichomonas vaginalis

23

C/F

-

Dx

-

Tx Morphology n’ stuff

Painful vaginal itching Burning and pain on urination (micturation) Yellow-green malodorous discharge Urethra+vaginal involvement in females Urethra+prostate gland involvement in males Examination of vaginal discharge  highly motile Urine exam  ↑ # present Metrondiazole – to patients sexual partner • Sexually transmitted • No oocyst – only flagellated trophozoite ( highly motile)

6 C/F

Naegleria fowleri - Acute meningitis  fatal (95%) within one week - Fever, headache, stiff neck, nausea, vomiting, short hx of swimming earlier - Sudden deadly infection in AIDS/transplant patients Dx - CSF exam  for motile amoeba and ↑ neutrophil count, low glucose & ↑ protein (identical to bacterial meningitis, however Gram stain will show no bacteria) - WBC  ↑ count suggests infection Tx - Amphotericin B (anti-fungal drug) Morphology • Amoeba n’ stuff • Lives in freshwater lakes Q what is the treatment of cryptococcers neoformans?  amphoteran B – for cryptococal meningitis – reaches CSF 7 C/F

Acanthamoeba species - Chronic, slow granulomatous brain infection  fatal w/in one year - Over weeks: fever, headache, seizures, focal neuro-signs - Corneal infection (Keratitis)  assoc.w/contact lens (cleaned in non-sterile solutions) Dx - CSF + brain tissue  for cysts + mature trophozoites - Corneal scrapings Tx - Multiple antifungal drugs (prognosis ↓ ) - Corneal transplant or antimicrobial drugs Morphology • Amoeba  cyst in brain n’ stuff • Case of chronic meningoencephalitis • Lives in freshwater lakes, soil, swimming pools Q healthy pt. w/ contacts – dev ulcerative lesion of eye  acanthamoeba – freshwater lakes 8 C/F

Toxoplasma gondii (Torch org.) - Congenitally acquired • Still birth  chorioretinitis, blindness, seizures, mental retardation/syndromes

•

-

Normal infants  chorioretinitis (which may lead to blindness) in adolescence Immunocompromised patients • ↑ susceptibility

•

Dx

-

Infection includes  encephalitis presenting as brain mass, chorioretinitis, lymph node-liverspleen enlargement, pneumonia Most infections: Benign and asymptomatic Symptomatic disease: involves cell destruction, reproduction, cyst formation Serology  ↑ IgM + IgG Biospy  from lymph nodes, brain, myocardium, body fluids (including CSF, amniotic or bronchoalveolar lavage fluid) can be examined for organisms CT scan  mass in brain Examination of retina

24

Tx Morphology n’ stuff

Q Q

Sulfadiazine/Clindamycin • Transmission  Ingestion of oocysts in raw port  Inhalation of oocysts from cat feces (80% of cats infected)  Pregnant women should avoid cats • Oocyst (infective) + Trophozoites • Found in birds, humans but essentially in cats 30yr old vet, usits ob exam—mild cervical lymphadenopathy, px-spiranycin – child  toxoplasma gondi beses of hydrocephalus cerebral calcification Which of the following infections agents cannot complete its entire life cycle in the Toxoplasma gondii human without resorting to stages in other living organisms:

9 C/F

Pneumocystis carinii - Interstitial pneumonia w/fever + dry cough b/c invades lungs at early stage - ↑ association in AIDS patients (CD4 count < 200) causing PCP Dx - Silver stain  ‘Flying saucer’ appearing fungi in any of following: • Saline induced sputum • Bronchoalveolar lavage w/bronchoscope • Bronchial wall biopsy - X-ray  interstitial pneumonia w/diffuse infiltrates Tx - Trimeth/sulfamethazole Morphology • Flying-saucer appearing fungus N’ stuff • Transmission in early age by resp.route that usually remains latent Q

Which of the following statements are untrue of pneumocystis carinii:

10 Org C/F

Malaria Plasmodium falciparum, P. vivax, P. ovale, P. malariae - High fever & shaking chills: episodic - Sweating (due to RBC rupture releasing merozoites) - Anemia - Hepatosplenomegaly/splenomegaly - Brain lung and/or kidney damage w/P. falciparum 1) Tertian malaria 1. episodes occur every 48 hours (P. vivax + P.ovale) 2. Benign: incubation period: 7-10 days 3. Malignant: Black water fever (resulting from kidney damage) 2) Quartan malaria 1. episodes occur every 72 hours (P.malariae) 3) P. Falciparum 1. irregular episodes occur every 36-48 hrs 2. Most common and deadly - Blood smear  Trophozoites (diamond-ring shaped) - Chloroquine + Primaquine (P.ovale + P.vivax) - Chloroquine (P.malariae + non-chloroquine resistant P.falciparum) - Quinine (Chloroquine resistant P.falciparum) Prophylaxis tx - Chloroquine - DOC - Mefloquine (if choloroquine resistance present)

Dx Tx

Diagnosis is made by the serology; microscopy is of no value

Radical cure  Primaquine Morphology • Female anopheles mosquito n’ stuff • P.vivax + P.ovale  Hypnozoites=dormant in liver • African Americans resistant to:  P.vivax (lack RBC membrane antigen duffy a/b)  P.falciparum (↑ incidence of sickle cell anemia trait)

25

11 C/F

Leishmania Cutaneous leishmaniasis - L.tropica (incubation: 2 wks – 2 months) - single ulcer (red papule) at site of bite (aka: Oriental sore) - heals in one year leaving depigmented scar Diffuse cutaneous - non-ulcerative nodular bite site (usually near nose) - no immediate tx required Mucocutaneous - L.braziliensis ((incubation: 2 wks – 2 months) - ulcers on mucus membranes after first ulcer heals - ulcers erode nasal septum, soft palate and lips (can last 20-40 yrs) Visceral leishmaniasis (aka: Kala-azar) - L.donovani (incubation: weeks to 1 yr) - common in young, mal-nourished children - fever, chills, sweating, diarrhea, anemia, anorexia, weight loss, hepatosplenomegaly, kidney damage - fatal (usually) Dx - Look for protozoa in: • Blood smear • Biopsy of skin lesions, spleen, liver, bome marrow - Leishmanin skin test • Negative in immunocompromised patients • R/o diffuse cutaneous & active visceral leishmaniasis - Serological test • Aldehyde test Tx - Arsenical drug - Amphotericin B (Mucocutaneous leismania) Morphology -Promastigote: Flagellated sandfly (bite) n’ stuff -Amastigote: non-flagellated in phagocytic cells of reticuloendothelial system -Zoonotic: carried by rodents, dogs & foxes -Vector: Sand flies Q Leishmania donovanum produces: Amastigotes which are seen in the human reticuloendothelial system

12 C/F

Dx Tx

African Trypanosoma Trypanosome rhodesiense & gambiense African Sleeping Sickness - Hard, red painful skin ulcer at site of tsetse fly bite (heals in 2 wks) - Intermittent Fever (due to variable surface glycoproteins), headache, lymph node swelling - CNS symptoms: daytime drowsiness, difficulty walking, slurred speech, coma, death • West African Sleeping sickness  Slow progessing fevers, late neurological symptoms • East African Sleeping sickness  More severe, rapid cycling of fevers, neuro-symptoms and death within weeks-tomonths - Blood, spinal fluid, lymph nodes  Visualize trypomastigotes - Serology  ↑ IgM - Suramin, Melasoprol

26

Morphology N’ stuff

Q

• • • • •

Tsetse fly bites Contaminated blood transfusion Trypomastigote: motile, flagellated; in blood, lymph nodes, CNS Trypomastigote & epimastigote: in tsetse flies As antibodies are formed by the human body against a particular VSG, the trypanosome will produce a progeny with a different VSG causing recurrent feveres In which of the following infections would you not expect to Trypansoma brucei rhodesience find intracellular amstigote forms:

13

American Trypanosoma Trypanosome cruzi C/F Chagas’ disease - Chagoma: hardened red area at site of parasite entry - Ac. Chagas’ dz: fever, malaise & swollen lymph nodes • Meningoencephalitis • Acute myocarditis w/tacchycardia, EKG changes - Intermediate dz: low levels of parasites in blood w/positive antibodies against T.cruzi but no symptoms (most people remain in this phase for life) - Chronic Chagas’ dz: Cardiomyopathy (dilated heart, heart failure, arrhythmias) along with megacolon (causing constipation/ab pain) and megaesophagus (difficulty+pain swallowing, vomiting of food) Dx - Blood, spinal fluid, lymph nodes  Visualize trypomastigotes - Xenodiagnosis (ac. Dz)  40 lab grown reduvid bugs are allowed to feed on a patient; one month later bug’s intestinal contents are examined for the parasites Tx - Nitrofurtimo (acute dz) - No tx for chronic manifestations Morphology • Trypomastigote: motile, flagellated; in blood (extracellular) N’ stuff • Amastigote: intracellular & non-motile – present in macrophages of lymph nodes, heart, brain • Trypomastigote & epimastigote: in kissing bug • As antibodies are formed by the human body against a particular VSG, the trypanosome will produce a progeny with a different VSG causing recurrent feveres • Kissing bug (reduvid bug) defecates on human skin while feeding • Trypomastigotes present in feces tunnel into skin • Contaminated blood transfusion 14 C/F

Balantidium Coli - diarrhea ( by consuming contaminated food, water, pig feces) - most patients: asymptomatic Dx - Fecal exam: Identify trophozoites or cysts in stool Tx - Tetracycline Morphology • Ciliated trophozoites N’ stuff • Largest parasitic protozoan in intestine 15 C/F

Isospora/Microsporidia - Severe diarrhea - Malabsorption in AIDS patients Dx - Fecal exam: Identify oocysts in stool - Biopsy - Eosinophilia Tx - Trimeth/sulfamethazole - Abendalzole can treat microsporidia Morphology • Ciliated trophozoites N’ stuff • Largest parasitic protozoan in intestine Q 24 yr AIDS pt. – chronic ab pain, low greade fever, darrihea, malabsorption, oocyts in stool. Which causes org?

 isopora belli – prod cysts ( oocysts)

27

Intestinal Nematodes (Roundworms) 1 Ascaris lumbricoides C/F - Asymptomatic - Abdominal cramping - Dry cough + fever while larvae are in lungs - Children may become malnutritioned as worm competes for food Dx - Fecal exam  for eggs (ova) - Sputum  may reveal larvae - Eosinophilia Tx - Mebendazole (paralyzes worm & prevents it from migrating out of SI) - Albendazole Morphology • Adult attains a length of 20-30 cm N’ stuff • Ingests eggs • If treated incorrectly, worm will migrate out of GI tract 2 C/F

Necator americanus (aka Hookworm) - Diarrhea, abdominal pain, weight loss - Iron deficiency anemia - Itching at site of skin penetration + rash - Occasional cough with blood sputum Dx - Fecal exam  for eggs - Sputum  larvae - Eosinophilia Tx - Mebendazole - Albendazole Morphology • Adults about 1cm length N’ stuff • Larvae penetrate thru skin • Ancyclostoma duodenale is another species of hookworm 3 C/F

Strongyloides stercoralis - Vomiting, diarrhea, anemia, weight loss - Occasionally fatal due to massive autoinfection in immunocompromised hosts Dx - Fecal exam  for larvae (no eggs present) - Enterotest  swallow long nylong string and later pull out – might show larvae - Sputum  larvae - Eosinophilia Tx - Thiabendazole - Albendazole Morphology • Larvae penetrate skin N’ stuff • Autoinfection • Adult females 2 mm long Q Which of the following diseases can be prevented by avoiding contact of naked skin Stongyloids infection with soil: 4 C/F Dx

Tx

Trichinella spiralis - Fever, abdominal pain, diarrhea - Muscle aches as larvae might migrate to skeletal muscles - Severe cases: larvae might migrate to heart and brain - Serologic tests - Biopsy: Muscle - Increase levels of muscle enzymes circulating in blood - Eosinophilia - Mebendazole, Tiabendazole

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Morphology N’ stuff

• • •

↑ assoc.w/port (always cook or freeze prior to consumption) Ingestion of encysted larvae (often found in raw pork) Cysts in skeletal muscle

5 C/F Dx

Trichuris trichiura (aka: Whipworm) - Diarrhea + Abdominal pain - Fecal exam  eggs - No eosinophilia Tx - Mebendazole - Albendazole Morphology • Eggs must incubate in moist soil for 3-6weeks before they become infected N’ stuff • Transmission via ingestion of eggs • Eggs look like a football with polar bumps on each end • Adults whip-shaped (3-5 cm length) Q A young child is admitted to your care. You find that he is anemic with a very low Mebendazole and iron lever of serum iron you order a stool specimen to be examined for ova and parasites. replacement The laboratory informs you that the feces contains egg of Trichuris, Ascaris and Hookworm. The correct treatment would be: Q Which one of the following parasitic nematodes does not cause a pneumonitis in the Trichuris trichuria human: (Whipworm) 6 C/F Dx

Enterobius vermicularis (aka Pin worm) - Severe perianal itching - Scotch-tape test - Perineum examination at night  may show adult worms with eye - No eosinophilia Tx - Mebendazole & Albendalzole Morphology • Female migrates to perianal area at night to lay eggs N’ stuff • Transmission via ingestion of eggs • Adult worms 1 cm long Blood and Tissue Nematodes (Roundworms) 1 Onchocerca volvulus C/F - Skin nodules (containing adult worms) - Pruitic rash w/darkened pigmentation - Dry scaly skin (aka Lizard skin) - River Blindness b/c microfilariae migrate thru eye Dx - Skin Biopsy for microfilariae Tx - Ivernectin (kills microfilarial stage) Morphology • Filariae (threadlike adult roundworms) N’ stuff • Give birth to live offspring called microfilariae transmitted by black fly • Vector = black fly (in rivers, streams; disease known as river blindness) • Common in Africa and Central/South America • Disease caused by allergic rxn to both microfilariae & dead worms 2 C/F

Dx

Wuchereria bancrofti - Filarial Fever (febrile episodes w/headache and swollen lymph nodes) - Elephantiasis • Following repeat infections, fibrous tissue form around dead filariae in lymph n. • Plugging the lymphatic sys. Resulting in swelling of legs + genitals • Thick scaly skin covers edematous lower extremities --> look like elephant legs - Microfilaria in blood drawn at night - Biopsy - Serology - Tropical pulmonary eosinophilia (↑ IgE)

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Tx Morphology N’ stuff Q

Diethylccarbamzine • Filariae (threadlike adult roundworms; live offspring aka microfilariae) • Allergic response to both microfilariae + dead worms in lymphatic sys • Vector: mosquito Mosquito control is useful in prevention of disease caused by: Wucheria bancrofti

3 C/F

Dracunculus medinensis (aka: Guinea worm) - Allergic symptoms occur during the release of microfilariae - Nausea, vomiting, hives, breathlessness Dx - N/a Tx - Drive a small stick under the part of the worm’s boy that is looped out of skin - The stick is twisted each day to pull out the 100cm Dracunculus Morphology • Larvae penetrate the intestine and mature beneath the skin N’ stuff • Ingested when drinking freshwater Q The life cycle of which parasite involve being transmitted by Dracunculus (Guinea worm) drinking water containing copepods: 4 C/F

Cutaneous Larva migrans (dog hookworm) - Creeping eruptions • Larvae of dog and cat hookworms penetrate the skin and migrate beneath the epidermis ( a few cm/day ) • Raised red itchy rash moves w/advancing larvae Dx - Biopsy of advancing edge of rash Tx - Thiabendazole, Albendazole Morphology • Larvae of god and cat tapeworms N’ stuff • Common in southwestern USA • Human tissue – invasive nematodes such as Necator americanus and Srongyloides can produce similar creeping eruptions 5 C/F

Visceral Larva migrans (aka: Toxocara canis – dog roundworm) - Toxocariasis • Migration of larvae thru body • Fever, diarrhea, wheezing, hepatitis, visual loss (from chorioretinitis) Dx - Seriology, eosinophilia Tx - Diethylcarbamazine, Albendazole Morphology • Larvae of dog roundworms, which CAN NOT mature in human N’ stuff • Transmission via ingestion of eggs Q You are a pediatrician in Georgia and your patient has cholisretinitis of both Order of stool specimen to eyes. You suspect he has an infection with Toxocara (cause of visceral larva be examined for ova migrans) which of the following is not an appropriate course of action for the physician to pursue:

Platyhelminthes (Flat Worms) 1 Schistosomes

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C/F

Schistosomiasis • Pruritic skin rash at site of penetration • Katayama fever (acute schistosomiasis)  Itching at first  Weeks later fever, hives, headache, weight loss, cough lasting 3 weeks - Complications caused by immune rxn against eggs released by adults in veins surrounding intestine or bladder resulting in: • Liver: fibrosis of portal venous sys leading to portal htn • Lung: fibrosis of pul.arterioles lead to pul.htn • Intestine: deposits of eggs lead to inflammatory polyps Dx - Stool/Urine samples: demonstration of org - Eosinophilia - Ultrasound of liver: liver disease Tx - Praziquantel (immediate exacerbation of symptoms followed by improvement) - Control; disposal of human fecal waste and destruction of intermediate host (snail) Morphology • Molecular mimicry N’ stuff  Incorp of host antigens onto their surface fools host’s immune system into thinking the schistosomes are not foreign - Penetrate thru exposed skin - Eggs must reach freshwater to hatch therefore schistosome cannot multiply in humans - Intermediate host: freshwater snail - TREMATODES --> eggs, mature larvae (called cercariae) male/female adults Q Which of the following is not usually diagnosed by examination Schistosoma haematobium infection in urinary of a stool specimen for the presence of eggs: tract -

2 C/F

Taenia solium (aka: Pork tapeworm) - Intestinal infection usually asymptomatic - Cysticercosis; eggs hatch within small intestine and larvae travel to muscle, CNS, eye - Form calcified cysts that are inflammatory - Blindness - Neuro-manifestations (seizures, focal neuro-deficits, hydrocephalus, CSF-drain block) Dx - Fecal exam --> eggs or gravid proglottids - CT scan --> brain (calcification) - Biopsy --> muscle (cysticerci) - Eosinophilia w/cysticercosis Tx - Praziquantel, Albendazole - Second choice for all tapeworms: Niclosamide Morphology - Cysticerosis (round, fluid-filled bladder w/larval form within) occurs with ingestion of eggs N’ stuff - Neurocysticercosis are cysts in brain - Ingestion of undercooked pork containing larvae common transmission - Can grow up to 2-8 meters - CESTODES --> scolex head with HOOKS Q Which of the following is most likely to cause cysticercosis in Eating taenia solium egg (onchosphere humans: larvae) 3 C/F

Taenia saginata (beef tapeworm) - Usually asymptomatic - Occasional ab discomfort, weight loss, diarrhea Dx - Fecal exam --> eggs or gravid proglottids Tx - Praziquantel Morphology - Ingest undercooked beef containing larvae stage common transmission N’ stuff - Scolex --> head w/SUCKERS (no hooks) - Gravid proglottids --> contains eggs & uterus has more than 15 pairs of lateral branches - Can grow to 10 meters in length 4 C/F

Diphyllobothrium latum (Fish tapeworm) • Nonspecific abdominal symptoms • Vit. B12 def – anemia

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Dx Tx Morphology N’ stuff

Identify eggs or gravid proglottids Praziquantel - Can grow to 45 meters in length - Ingestion of larvae in raw freshwater fish

5 C/F

Hymenoplepsis nana (aka: Dwarf tapeworm) • Usually asymptomatic • Occasional ab-discomfort, nausea/vomiting Dx - Fecal exam for eggs - Proglottids too small to see Tx - Praziquantel Morphology - Adults grow to 15-50 mm N’ stuff - Fertilized transmitted eggs are infectious (auto-infection) 6 C/F

Echinococcus (aka: Hydatid disease) - Hydatid cysts • M/c in liver+lungs w/ cysts enlarging every 1-20 years (may calcify) • Liver: ab-pain, palpable liver mass, biliary obstruction, fatal • Lung: cyst may rupture, causing cough or chest pain - Leakage of hydatid cyst fluid can cause a severe allergic rxn Dx - CT scan or ultrasound --> liver or lung to see cysts - Serology Tx - Surgical removal of cysts w/caution b/c fluid leakage causes ↑ anaphylactic rxn - Mebendazole or Albendazole - Injection of ethanol into cyst by CT can guided needle Morphology • Transmission via ingestion of fertilized eggs N’ stuff 7 C/F

Fasciolepsis buski - Inflammation of SI; ulceration and hemorrhage - Abdominal discomfort; diarrhea indicate severe infection - Duodenum involvement (metacercariae are scraped from husk, swallowed and develop into immature flukes here and attach to mucosa of SI w/2 suckers Dx - Stool exam --> large, golden bile stained eggs Tx - Preziquantel or secondary choice; niclosamide Morphology • Largest, most prevalent intestinal fluke N’ stuff • Humans ingest encysted larval stage (aka Metacercariae) • Egg production is initiated 3 months after initial infection • Pigs, dogs, rabbits = reservoir hosts in china, Vietnam, Thailand, indonesia 8 C/F

Fasciola hepatica aka Sheep liver fluke - Migration of larval worm thru liver = irritation of tissue, hepatomegaly - Right upper quadrant pain, chills, fever, eosinophilia - Bile duct – mechanical irritation, toxic secretions leading to hepatitis, epithelial hyperplasia and biliary obstruction (also cirrhosis) Dx - Stool examination – eggs - Bile examination Tx - Bithiomol or benzimidazole Morphology • Found in sheep, cattle, humans N’ stuff • Larval flukes migrate thru duodenal wall across peritoneal cavity, penetrate liver capsule, pass thru liver parenchyma and enter bile ducts to become adults • Approx. 3-4 mo. After initial infection adult flukes start producing eggs in stool • F. hepatica are present in bile • F. buski are limited to small intestine 9

Opisthorchis sinesnsis (Clonorchis sinesnsis) aka Chinese liver fluke

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C/F

Dx

-

Tx

Morphology N’ stuff

Mild & asymptomatic Severe infection in bile duct produces fever, diarrhea, epigastric pain, hepatomegaly Biliary obstruction and chronic infection result in adenocarcinoma of bile ducts Invasion of gall bladder = cholecystitis, cholelithiesis, impaired liver function/abscess Stool exam = eggs Duodenal aspirates (mild infections) Eosinophilia + ↑ serum alkaline phosphate levels in acute infection Preziquantal (DOC) Prevention by avoiding uncooked fish and sanitation improvement • Found in China, Japan, Korea, Vietnam • Traced to consumption of raw, pickled, smoked, dried fish • Dogs, cats, fish eating mammals also serve as reservoir hosts

10 C/F

Paragonimus westermani aka Lung Fluke - Onset of disease coincides with larval migration assoc.w/fever, chills ↑ eosinophilia - Adult flukes in lungs produce inflammatory rxn initially w/fever, cough, ↑ sputum - Destruction of lung tissues progresses, cavitation occurs around worms - Sputum is blood stained and dark with eggs (aka Rusty sputum) + ↑ chest pain - Dyspnea, chronic bronchitis, bronchiectasis and pleural effusion - Chronic infection lead to fibrosis in lung tissue - Migration of larval worms may result in invasion of spinal cord + brain producing severe neurological disese (visual prob, motor weakness, convulsive seizures) - ‘Cerebral paragonimiasis’ Dx - Sputum, Feces examination = Golden brown eggs - Pleural effusion should be examined for eggs - CXR = infiltration, nodular cysts and pleural effusion - ↑ eosinophilia Tx - Preziquantal w/birthionol Morphology • Infective stage occurs at 2nd intermediate host – the muscles and gills of fresh water craps and N’ stuff cray fish • Ingested larval worm hatches in stomach and follows extensive migration thru intestinal wall to abdominal cavity then diaphragm finally to pleural cavity • Adult worm resides in lungs, produces eggs liberated from ruptured bronchiles and appear in sputum or when swallowed, feces Fungi 1 Malassezia furfur C/F - Pityriassis versicolor (Tinea vesicolor) - Hypo/hyperpigmentation patches on the skin (surrounding skin darkens w/sunlight) Dx - Potassium hydroxide (KOH) prep  reveals short, curved unbranched hyphae w/spherical yeast cells (spaghetti and meatballs morphology) Tx - Dandruff shampoo containing selenium sulfide Morphology • Superficial location N’ stuff • Spaghetti and meatballs 2 C/F

Exophiala werneckii - Tinea nigra - Dark brown to black patches on the soles of the hands (palms) and/or feet Dx - KOH prep  septate hyphae and budding yeast cells Tx - Dandruff shampoo containing selenium sulfide, ‘azoles’ Morphology • Brown-pigmented branched septate hyphae and budding yeast cells N’ stuff • Superficial location 3

Microsporum Species/Trichophyton species/Epidermophyton floccosum

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C/F

-

-

Dx

-

Tx Morphology N’ stuff

Dermatophytosis Tinea corporis (body)  ringworm Tinea cruris (groin)  jock itch Tinea pedis (feet)  athlete’s foot Tinea capitis (scalp) Tinea unguium (nail)  onychomycosis KOH Wood’s light/lamp  certain species will fluoresce under UV light Tropical imidazole • Secretes the enzyme keratinase which digests keratin

• •

Depending on particular species soil, animals, humans are reservoir Cutaneous location

3 C/F

Sporothrix schenckii aka Rose garden disease - Sporotrichosis - Subcutaneous nodule gradually appear at site of thorn prick - Nodule becomes necrotic and ulcerates - Ulcer heals but new nodules appear nearby along lymphatic tract Dx - Dimorphic - (culture grows at 25 degree C  branching hyphae) - (culture grows at 37 degree C  yeast cells) Tx - Oral potassium iodide, Amphotericin-B, Itraconazole Morphology • Found on rose thorns N’ stuff • Subcutaneous 4 C/F

Phialophora verrucosa/Cladosporium carrionii/Fonsecaea species - Chromobiastomycosis - Following a puncture wound, small, violet wart-like lesion develops - Clusters of these skin lesions deelop (resembling cauliflower) Dx - Skin scrapings with KOH prep  copper-colored cells (sclerotic bodies) Tx - Itraconazole - Local excision Morphology N’ stuff 5 C/F

Coccidioides immitis aka Valley Fever - Coccidiodomycosis - Asymptomatic - Pneumonia - Lungs, skin, bones, meninges (disemminated) Dx - Biopsy: lung, skin - Silver stain or KOH prep - Culture on Sabourauds agar - Serology - Skin test (for exposure only) Tx - Amphotericin-B, Itraconazole, Fluconazole Morphology • Common opportunistic infection in AIDS pt from southwest USA N’ stuff • Systemic location • Dimorphic morphology with mycelial formation w/spores at 25 degree C • Yeast formation at 37 degree C • Desert areas of the southwestern USA, California (San Joaquin Valley) and northern Mexico • Respiratory transmission 6

Histoplasma capsulatum

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C/F

Dx

-

Morphology N’ stuff Tx

Histoplasmosis Asymptomatic Pneumonia (calcified lesions seen on X-ray similar to TB) Lung, spleen, liver dissemination Mucocutaneous ulcers of nose, mouth, intestine Lung Biopsy w/silver stain, culture on Sabourauds agar revealing hyphae at 25 and yeast at 37 degree C (may disseminate to reticuloendothelial system) Skin test (for exposure only) Itraconazole Amphotericin-B (in immunocompromised patients) • Can survive intracellularly w/in macrophages • Systemic location • Dimorphic (no capsule) • Mississippi valley, birds & bat droppings are reservoir • Respiratory transmission

7 C/F

Blastomyces dermatitidis aka North American Blastomycosis - Blastomycosis - Asymptomatic (uncommon) - Pneumonia  lesions rarely calcify - Disseminated most commonly  w/weight loss, night sweats, lung involvement, skin ulcers (cutaneous) - Paracoccidiodies brasiliensis (South American blastomycoses) - Cultures of mold grow slowly - Produce chlamydospores resulting in  pulmonary granuloma - Initial lesions in lungs Dx - Biopsy of affected tissue (Lung, Skin) - Silver stain, culture, serology, skin test Tx - Itraconazole, Amphotericin-B, Ketoconazole Morphology • Dimorphic morphology N’ stuff • bLAST to get • No BLAST to have • Systemic location • Mississippi valley, bird/bat droppings reservoir + respiratory transmission 8 C/F

Cryptococcus neoformans - Cryptococcosis - Subacute or chronic meningitis presenting w/: • Headache, fever, vomiting, neurological or mental status changes - Pneumonia (self-limited) - Skin lesions (look like acne) Dx - India-ink stain of CSF  observe encapsulated yeast - Cryptococcal antigen test of CSF  detects polysaccharide antigens - Fungal culture Tx - Amphotericin-B + flucytosine (more superior combination) - Fluconazole Morphology • Most cases occur in immunocompromised patients N’ stuff • Systemic location • Polysaccharide capsule

• • • •

Yeast form only (not dimorphic)  37 degree C Produces Urease Found in pigeon droppings (reservoir) Respiratory transmission therefore mild symptoms

35

9 C/F

Candida albicans - Candidiasis in normal host • Oral thrush • Vulvovaginal candidiasis • Cutaneous (diaper rash, rash in skin folds of obese people) - Candidiasis in immunocompromised host • Thrush, vaginitis, cutaneous plus

 Esophageal  retrosternal chest pain, dysphagia, fever  Disseminated candidiasis  acquired by sick hospital pts resulting in multi-organ Dx Tx

-

Morphology N’ stuff

10 C/F

Aspergilius fumigatus/A.flavus/A.niger - Aspergillosis • Allergic bronchopulmonary aspergillosis (IgE mediated) -

-

Dx

system failure  Chronic mucocutaneous candidiasis KOH stain of specimen Silver stain of specimen Blood culture; growth must be respected Dependant on type of infection Thrush  swish/spit nystatin or imidazole Cutaneous infection  topical imidazole AIDS (thrush, esophageal, vaginal)  Fluconazole Systemic candidiasis  Amphotericin-B Chronic mucocutaneous candidiasis  Ketoconazole or amphotericin-B • Cutaneous or systemic • Normal inhabitant of skin/mouth/GIT (found in mucosa soon after birth) • Not found in blood • Pseudohyphae and yeast

-

-

-

• Asthma type rxn w/shortness of breath and ↑ fever Aspergilloma • (fungus ball) • assoc w/hemoptysis (bloody cough) Invasive aspergillosis • Necrotizing pneumonia • May disseminate to other organs in immunocompromised patients Alfatoxin • Consumption (produced by A.flavus) can cause liver damage + liver cancer Allergic bronchopulmonary aspergillosis ↑ IgE, ↑ IgG against aspergillis Sputum culture Wheezing patient + chest x-ray w/fleeting infiltrates Increased levels of eosinophils Skin test  immediate hypersensitivity rxn Aspergiloma  diagnose w/CXR or CT-scan Invasive aspergillosis  sputum examination + culture 36

Tx

-

Morphology N’ stuff

Allergic broncho. Aspergiliosis  tx w/corticosteriods Aspergiloma  removal via surgery Invasive aspergilosis  tx w/Amphotericin-B and other agents (rifampin, itraconazole) Poor outcome • Alfatoxin contaminate peanuts, grains and rice

• •

Morph  Branching septated hyphae Everywhere is a reservoir  Frequent lab contamination  Aspiration of aspergilius = asthma

11 C/F

Rhizopus/Rhizomucor/Mucor - Mucormycosis - Rhinocerebral (assoc.w/DM) - Starts on nasal mucosa – invades sinus and orbit (eye) and brain - Pulmonary mucomycosis Dx - Biopsy - Black nasal discharge Tx - Amphotericin-B - Surgery Morphology • Disease is rapidly fatal N’ stuff • Broad, non-septated branching hyphae(morph), saprophytic moids (reservoir) Fungi-like Bacteria 1 Actinomces israelii C/F - Mycetoma - Eroding abscesses of mouth, lung, GIT - Classified as: Cerviofacial actinomycosis, Throacic actinomycosis, Abdominal Actino. Dx - Examine tissue or pus from infection site  sulfur granules - Anaerobic culture Tx - Penicillin G - Surgery Morphology • Yellow ‘sulfur granules’ – microcolonies of actinomyces and cellular debris N’ stuff • Gram positive rods (beaded filaments) • Part of normal flora of mouth/GIT 2 C/F

Nocardia asteroids - Pneumonia - Formation of abscesses in the lung, kidney, CNS Dx - Gram stain - Modified acid fast (decolorized w/1% sulfuric acid instead of acid alcohol) Tx - Trimeth/sulfamethazole Morphology • Infections usually occur in AIDS patients N’ stuff • Never part of normal flora • Respiratory transmission

January 2003 Internals – More Questions #3 Difference bet/n pathogenic & non-pathogenic enteric bacteria

Lactose fermentation

37

on basis of: What is responsible for the outbreak of basically dysentery in rural area: Causes fever and inflammation: Which enzyme activates the plasma plasminogen system:

Human carrier Endotoxin Coagulase

#4 45-yr-old male w/alcohol abuse, periodontal disease, fever/chills, pneumonia with lung consolidation. CXR shows cavity in right lower lung; what type of bacteria involved: Which organism is likely to be implicated as a causes of urethritis persisting after antibioitic therapy for gonorrhea: 35-yr-old women presents to her gynecologist with complaints of buring on urination for 2 days. Dipstick test of her urine: Sexually active 18-yr-old women presents with fever of 102oF for the past After handling deer pt. eats and experiences fever, nonproductive cough, shortness of breath, lymphadenopathy and no skin lesions: Fever, chills, headache, myalgia, arthlargia. Ulcer with black base on right hand and epitrochlear lymphadenopathy. Patient knows to skin rabbits: Dairy farmer with fever, chills, myalgia, headaches, skin rash, vomiting. Spirochetes in blood. Early culture in serum shows enriched nutrient agar: Flea bites, rat infected shed, fever, chills, rash: Tick bites – chronic arthritis, knee + hip + facial muscle weakness due to lyme disease. Which org:

Anaerobic bacteria b/c organism is elsewhere + causing disease elsewhere (mixed infection)

Which of the following organism has been associated with production of anemia in infected individuals: Which of these parasite life cycle cannot be interrupted by sterilizing the feces of all infected people:

P. Vivax, N. Americana, D. Latum

Tularemia due to handling animals Fanciella (tularensis disease) Leptospira interrogans Endermic typhus – produced by rat fleas/ticks Erthema chronicum migrans

#6

More #6 Questions (usmle) Q 33 yr pt. headache, blurred vision, phys exam= pupil edema + ataxia. Head CT scan Q Ohio river, headache, fever, malaise + non-productive cough after few days Q Healthy pt. pusthetic, aortic valve  post op fever, bld culture done  bld spectrum antibiotics, 2 days later, shll febrole, which is most likely pathogen? Q 40 yr healthy, subcutaneous lesion in r. hand –cut w/ thorn. Fluchiant lesion Q diabetic pt. chronic sinusitis - no response to antibiotics Q cavernous sinus – mucor can enter to brain meningitis

Filariasis (Heartworm-b/c transmitted thru mosquito bite)

 Non dimorphic yeast. Found world wide  hishplasma capsulation  candida albicans

 rose garden d2- sporothrix  mucor  sinusitis inf

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