Micro Cheat Sheet #1 for PASS program

October 21, 2017 | Author: OJOSAZULESAK | Category: Streptococcus, Microbiology, Medical Specialties, Diseases And Disorders, Immunology
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created cheat sheet #1 for first pass video...


Micro Cheat Sheet (PASS Videos)

Staining Clues -

Gram (+) cocci – staph/strep Gram (-) cocci – Niserria/Moraxella Gram (+) rods – Bacillus, Clostridium, Listeria, Cornybacterium Gram (+) Branching rods – Nocardia, Actinomyces

Exotoxins (G-)

Exotoxin (G+ &G-)


A-B Component

Lipid A (toxic)

A = Toxin

Increased # Macrophages

Nickolsky’s Sign

B = Binding

Increased # Cytokines

Virulence -

Gram (-) pilli or fimbriae Gram (+) teichoic acid IgA proteus Capsules  largest capsule is in Neiserria Antiphagocytic Surface (Ex: S.pyogenes – M protein ; N. gonorrhea – pili ; S. aureus – protein A

Neurotoxins -

C. tetani  painful spasms C. botulinum  flaccid paralysis

Evade Killing -

Mycobacterium TB – “cord factor” (macrophages cannot breakdown bacteria so T cells surround and create granulomas) Listeria – jumps from cell to cell

Media -

MacConkey’s – ferments lactose EMB – eosin methylin blue – fecal stool (E.coli) Buffer Charcoal Yeast Agar – legionella Chocolate agar – Neiserria, Haemopolis o X factor = Heme ; V factor = NAD ***Anytime you see this, choose Chocolate agar


TCBS – Vibrio cholera – ferments sucrose turns orange

***Staph. pyogenes = Staph. aureus

(Old name for it)

***Strep. pyogenes is #1 cause for: o Lymphangitis (see red line going up arm), Impetigo, Necrotizing fasciitis, crysipelas (no blanching), and Scarlet Fever ( rash that spares palms and soles)

Skin Infections -

Cellulitis: flat, red, blanches Mastitis: cellulitis around the breast (mother’s should continue to breast feed) Balanitis: infection at the head of the penis Panniculitis: cellulitis around the abdomen


Periorbital cellulitis: infants, trauma (little kid with swollen eye) o S. aureus Orbital Cellulitis: proptosis, older pt. o S. pneumonia Carbuncle: nodular induration with infection Furuncle: hair follicle in the middle of the carbuncle; no pus Carbunculosis: deep skin infection o S. aureus Furunculosis: many infections of the hair shafts o Common areas – nap of neck, chest, legs Fasciitis: inflammation of the fascia o Plantar or necrotizing Folliculitis: infection of the hair shaft Blepharitis: infection of the eyelid

Mouth Flora -




S. pyogenes (GAS) S. pneumonia H. influenza IgA protease N. catarrhalis o N. gonorrhea o N. meningitides Peptococcus Low yield Peptostreptococcus Fusobacterium o “Trench Mouth”- pus from gums o Vincent’s Angina – painful ulcers at the back of the neck Actinomyces o Draining fistulas o Sulphur granules S. viridians o S. mutans ferments glucose  Dental  Subacute bacterial endocarditis o S. sanguis o S. salivarius

Stomach Flora -

H. pylori use campylobacter-like test to diagnose (positive turns green)

Urease (+) Bugs -


Proteus Pseudomonas Ureoplasma Nocardia Cryptococcus H. pylori S. saprophyticus Brucellosis

Curved Rods -

Vibrio Camphlobacter Listeria H.pylori

Small Intestinal Flora -

95% E.coli processes vit. K production of factors 2, 7, 9, 10 in liver

Small Intestinal Infections -

Cholecystitis Ascending Cholangitis Appendicitis Spontaneous bacterial peritonitis Abdominal abscess

***If there is a perforation, blame anaerobes  put in a draining site

E.coli makes... -

90% of vit. K Biotin – cofactor Folate – for rapidly dividing cells and for purine/pyrimidine synthesis o All pregnant mothers should be on folate 30-90 days prior to conception

E.coli Helps your body absorb… -

Vit. B12  use Schilling’s Test to determine B12 deficiency o Procedure: give B12 I.M. then give B12 radio-labeled) o If B12 is found in urine, then B12 deficiency  Then give radio-labeled intrinsic factor. If in urine, then deficiency and rule out pernicious anemia

Distal ileum and Colonic flora -

Proteus – 2nd line in UTI Klebsiella – 3rd line in UTI Serratia marscencens Citrobacter – infant with meningitis with cerebral abscesses Acenetobacter – immunosurpressed pt. on ventilator E.coli

Big MaMa Anaerobes -

Bacteroides fragilis – obligate anaerobe of GI S. bovis – big cause of colon cancer C. melanogosepticus – less big cause of colon cancer C. difficile – pseudomembrane colitis

Rectal Flora


GBS E.coli Listeria monocytogenes – really old/really young


Staph gram (+) in clusters Aureus Gold pigment Β – lactamase Coagulase + MSA – ferments mannitol #1 Osteomyelitis

Epidermitis White Pigment Deep to Skin Novobiocin Sensitive

Saprophyticus n/a Skin Novobiocin Resistant

Prosthetic devices

UTI; honeymoon cystitis


S. aureus o Catalse + - breaks down H2O2 o Β – lactamase – always “garage door” o Coagulase & staphlokinase – eats through clots o MCC of Acute Endocarditis o MCC of osteomylitis o MCC of death in burn pt. in first week  After first week is pseudomonas o Toxins:  Scalded Skin Syndrome – Exfoliating (Nikolski Sign), red rash all over body except for palms and soles  Toxic Shock Syndrome – Traid (high fever, hypotension, rash); retained tampon, palms and soles  Lecithinase – causes skin infections (subcutaneous fat)  Enterotoxin – causes food poisoning (dairy products- gastroenteritis; Fast- 2-6 hours)


Enzymes Continued: o Lipase (breaks down fat) – panniculitis, folliculitis, mastitis o Elastase (breaks down elastin) – Bullous Emphysema (pneumatocelle)  Comes from neutrophils  Elastin + collagen = CT

 A1Antitrypsin (liver) – inhibits elastase  Panacinar (panlobular) – aging  Centriacinar (centrilobular) – smoking  Distal (periceptal) - bullous o Collagenase (skin & bone – breaks peptide bonds)  MCC of osteomyolitis (2nd is Salmonella)  Type IV (BM)  Type III (endothelium – arteries affected)  Type II (CT)


S. epidermidis o Catalase + o White pigment o Resides under the skin o MCC of Shunt infections and central line infections o Tx: Vancomycin  Linezolid for vancomycin resistance  Keep pt in a negative pressure room


S. saphrophyticus o Catalase + o No pigment o Frequent cause of UTI  Ages 5-10 and 18-24 (post coital UTI, no circumcision)  E.Coli is MCC of UTI’s


Strep  gram + cocci in chains o Lancfield Groups – A, B, C, D o Types of helolysis:  α hemolysis – partial (green zone)  β hemolysis – complete (clear zone)  γ hemolysis – no hemolysis (red zone) o Streptokinase – responsible for the β hemolysis (clear zone)  Breaks clots – converts plasminogen to plasmin


If ANY past Strep infection, it will NOT work  use tPA…  Converts plasminogen to plasmin – breaks clots  Binds fibrinogen – will not clot again

Thrombolytics o Urokinase – opens fistulas and grafts o Streptokinase – Beta hemolytic – acute MI o Tissue Plasminogen Activator (tPA) – acute MI, acute Stroke (within 3hrs) ***Antidote for all three = aminocaproic acid


S. pneumonia (pneumococcus) o Gram + diplococcic o Alpha hemolysis (green zone) o 80 Strains o Pneumococcal vaccine (pneumovax) covers 23 strains (98% coverage)  Who should be on it:  >65y/o ; >2y/o with Sickle Cell (spleen-encapsulated organisms)  End Organ Failure  PSGN (post strepto glomerulo nephritis) - skin and throat can cause this o Strain 12


S. pyogenes (GAS) o Beta hemolytic (clear zone) o 70 Strains o MCC for throat infections  Can lead to rheumatic fever nd o 2 MCC of Skin infections


S. agalactiae (GBS) o MCC of neonatal Sepsis o Beta hemolytic (clear zone)


S. viridians (GDS – mutans, saguis, salivarius) o Alpha hemolytic (green zone) o MCC of Subacute Bacterial Endocarditis  Septic emboli to brain  Roth Spots – emboli to retina  Osler nodes – emboli to fingers (painful)  Splinter hemorrhages – emboli to nail beds  Pitting on nail beds = psoriasis ; spooning on nail beds = iron deficiency  Janeway lesions – emboli to toes o Previous Damage to heart valve predispose to SBE  this is why dentists ask if have a past history of rheumatic fever; damage to valves o Tx: Amoxicillin


Enterococcus (faecalis, faeceum) o Anaerobic o λ hemolytic (red zone) o likes immunocompromised pt o Nitrite Negative UTI o Tx: Vancomycin  MOA: cell wall inhibitor (inhibits phospholipid carrier [irreversible]) and Tx for all gram +  Toxicity: Red Man Syndrome, Intense histamine release (not allergic), ototoxicity, nephrotoxicity (tubules and interstitium)  Used for: MRSA, S. epidermidis, and enterococcus  If MSSA, then switch over to napacillin


Meningitis o 0-2 month  GBS  E.coli  Lysteria o 2mo-10years

 S. pneumoniae  N. meningitides o 10-21years  N. meningitides  S. pneumoniae o >21years  S. pneumonia


Cornybacterium Diptheriae o Chinese Letters o Toxin that ADP-ribosylates EF-2  Affects translocation of protein synthesis o Toxin may also cause Heart Block o Intracellular pathogen o Cells die, slough off, and mix with mucus, forming a grey membrane in posterior pharynx o Do NOT scrape: will hemorrhage profusely o DPT: 2m, 4m, 6m, 18m, 5-6y o TX: antitoxin first; antibiotic (toxin is hurting the pt, not the bug)


ADP-ribosylators o Gs: Vibrio Cholera, ETEC o Gi: Bordatella pertussus o EF2: C. diptheriae, pseudomonas


Cause Heart Blocks o Lyme Disease o Legionella o Typhoid Fever o Diptheria o Chaga’s Disease  What parts of the body does it like to chew on? Ganglia no release of VIP (relaxing hormone)  lower esophageal sphincter remains constricted  no GURD

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