Microbiology

normal flora on skin

Propionibacterium acnes
staphylococcus epidermidis
diphtheroids
transiently: S. aureus

normal flora of oral cavity

Viridians Streptococci
Branhamella species
Prevotella melaningogenicus
Actinomyces species
Peptostreptococcus species
anaerobes

normal flora of nasopharynx

oral organisms
transiently: S pneumoniae
Haemophilus species
N. Meningitidis

normal flora of the Stomach

rapidly becomes sterile

Normal flora of the Small intestine

scant

normal flora of the Colon

Bacteroides species (anaerobes)
Clostridium species (C.diff)
Fusobacterium species
E.Coli
Proteus species
Pseudomonas aeruginosa
enterococcus species
other bacteria and yeast

normal flora of the vagina

childbearing yrs:
Lactobacillus species, yeasts, strep species
Prepuberty/post-meno:
Colonic flora and skin flora

Endotoxin vs Exotoxin:
source
chemistry
toxicity
heat stability

Exotoxin: secreted from gram + and gram -; polypeptide; highly toxic (vaccines available); heat labile
Endotoxin: from the outer membrane of most gram -'s and Listeria; lipopolysaccharide; low toxicity (no vaccine available); heat stabile

Superantigens

bind directly to MHC II and T-cell R simultaneously, activating large numbers of T cells to stimulate release of IFN-gamma and IL-2

Toxin description: S.aureus

TSST-1 superantigen = toxic shock syndrome toxin (fever, rash, shock); enterotoxins = food poisoning, exfoliation (scalded skin syndrome)

toxin description: S.pyogenes

Erythrogenic toxin causes toxic shock-like syndrome: Scarlet Fever
Steptolysin O is a hemolysin; antigen for ASO Ab, which is used to dx Rheumatic fever

ADP ribosylating A-B toxins

interfere w/ host cell function. B(binding) component binds to a receptor on surface of host cell, enabling endocytosis. A(active) component then attaches an ADP-ribosyl to a host cell protein (ADP ribosylation), altering protien funciton.

Toxin description: Cornebacterium diptheriae

inactivates elongation factor (EF-2) {similar to pseudomonas exotoxin A}; causes pharyngitis and 'pseudomembrane' in throat

Toxin description: Vibrio Cholerae

(exotoxin) ADP ribosylation of G protein stimulates adenylyl cyclase; increases pumping of Cl- into gut and decreases Na absorption. H20 moves into gut lumen; cuases voluminous rice-water diarrhea

Toxin Description: E coli.

(exotoxin) Heat labile, stimulates AC; heat-stable stimulates GC {"Labile like the Air; stable as the Ground"}

Toxin description: Bordetella pertussis

(exotoxin) increases cAMP by inhibiting Galpha(i); causes whooping cough; inhibits chemokine-R, causing lymphcytosis

Toxin description: Clostridium perfringens

(exo) alplha toxin causes gas gangrene; get double zone of hemolysis on bd agar

Toxin Description; C.tetani

(exo) blocks the release to inhibitory n.t.s (GABA and glycine); cuases 'lock jaw'

Toxin description: C. botulinum

(exo) blocks release of Ach; cuases anti-cholinergic symptoms, CNS paralysis, esp cranial nerves; spores found in canned food, honey (causes floppy baby)

Toxin description: Bacillus anthracis

(exo) - 1 toxin in the complex is an AC

toxin description: Shigella

(exo) Shiga toxin (also produced by e coli) cleaves host cell rRNA (kills intestinal cells); also enhances cytokine release, causing HUS (hemolytic uremic syndrome) - occurs after bloody diarrhea

Identification of Gram + bacteria schema (staph and strep)

NO-StRESS: Novobiocin-Saprophyticus is resistant; Epidermidis is sensitive
OVRPS: Optochin - Viridans is resistant; Pneumoniae is sensitive
B-BRASS: Bacitracin-group B strep are resistant; group A are sensitive

Congo Red uses

Amyloid, apple-green birefringence in polarized light (b/c of beta-pleated sheets)

Giemsa's stain uses

Borrelia; plasmodium; trypanosomes; chamydia

PAS stain uses

Stain glycogen, mucopolysaccharides, used to dx Whipple's dx (T.whipplei, arthralgia and malabsorption)

Ziehl-Neelsen uses

Acid-fast bacteria (all mycobacteria: M.tuberculosis, M.Leprae and atypicalMycobacterium)

India ink uses

cryptococcus neoformans (yeast like fungus w/ a capsule that doesn't pick up ink - therefore stain looks like halos)

silver stain uses

Fungi, Legionella

Bacteria whos toxin is encoded in a lysogenic phage:

ABCDE
ShigA-like toxin, Botulinum toxin (certain strains), Cholera toxin, Diptheria toxin, Erythrogenic toxin of strep.pyogenes

obligate aerobes

"naggin pets must breath"
Nocardia, Pseudomona aeruginosa, myocbacteriaum tuberculosis, bacillus

Obligate anaerobes

ABC's of anaerobes
Actinomyces, Bacteroides, Clostridium (lack catalase and/or superoxide dismutase - thus susceptible to oxidative damage)

obligate intracellular organisms

"when it's Really Cold, you must stay inside"
Rickettsia, Chlamydia

ureas positive bugs

H.pylori, proteus, klebsiella, ureaplasma

alpha hemolytic bacteria

(green ring forms around colony on bd agar)
strep.pneumoniae (catalase -; optochin sensitive)
Viridans.streptococci (catalase -; optochin resistant)

beta hemolytic bacteria

(clear area of hemolysis on bd agar)
staph.aureus (catalase and coagulase +)
Strep.pyogenes = group A (catalase -, bacitracin sensitive)
strep.agalactiae = group B (catalase -, bacitracin resistant)
listeria monocytogenes (tumbling motility, meningiti

transpeptidase NZ

cross links the peptidoglycan layer... is also called penicillin binding protein b/c is the target of pen's

Teichoic acid

only found in gram + cell wall; antigenic and used for serology

murein lipoprotein

found in gram - peptidoglycan layer and extends to surface membrane

lipopolysaccharide (LPS)

found outer surface of the outer membrane of gram - envelope; has three components: O-sp side chain; core polysaccharide; lipid A (endotoxin) = endotoxic shock when our immune system degrades cells

gram + rods that produce spores

Bacillus and clostridium

what gram + has an endotoxin (unique b/c all other endotoxin bacteria are gram -)

Listeria

quelling rxn

bacteria are mixed w/ Ab's that bind the capsule. Wehn these Ab's bind - the capsule swells w/ water, and this can be visualized microscopically.

Bugs w/ positive quelling rxn

strep.pneumoniae, H.influenza (esp serotype B), Neisseria miningitidis, Klebsiella pneumoniae (The capsule on these bugs is antiphagocytic)

facultative intracellular bugs

Listeria moncytogenes
salmonella typhi
Yersinia
Francisella tularensis
brucella
legionella
mycobacertium

effects of septic shock

vasodilation
Myocardial depression
acute renal failure
ARDS
Hepatic failure
encephalopathy
DIC

transformation

uptake of naked DNA into recipient. reproduced by recipients machinery. dna homology necessary.

transduction

bacteriophage (virus) - carries a piece of bacterial DNA form one bacterium to another. Absorption (binding) and penetration occurs.

conjugation

one bacteria has the self-transmissible plasmid (F plasmid). The other is F-, and therefore a recipient.

transposons

mobile genetic units; insert themselves into donor DNA and homology is not req'd. Leads to rapid spread of genes (including drug resistance genes).

Bugs w/ ADP ribosylating toxins

Corynebacterium diphtheriae
vibrio cholerae
e.coli
bordetella pertussis