Bugs Flashcards
Staph aureus/epidermidis
characteristics
gram+
cocci
clustered
catalase +
S. aureus
diseases
Cutaneous infection (foreign body associated) Toxin mediated diseases -> superantigens - scalded skin syndrome - TSS (TSST) - food poisoning, ingestion of SA toxin pneumonia (esp. in-patient) foreign body assoc. infection bacteremia/endocarditis
causative agents of bacterial endocarditis
S. aureus
Streptococci ‘viridans’
coagulase neg. Staphylococci
Steptococcus characteristics
Gram+
cocci
chains
catalase -
Pertinent Strep family members + diseases
S. pyogenes “Group A Strep”
- pharyngeal infection (M-protein, recovery requires M-protein antibody)
- skin and wound infections (spreading infections)
S. pneumoniae (diplococci)
- non-invasive pneumonia, sinusitis, otitis media, bronchitis
- invasive meningitis, bacteremia/septicemia, pneumonia + septicemia
- grow and evade -> CAPSULE
“Viridans streptococci”
- bacterial endocarditis
- alpha or non-hemolytic
- abundant in mouth (dental carries)
Enterococci
M-protein function
surface exposed protein
- inhibits phagocytosis and killing by PMNs
- enhances adherence to epithelial cells
Post-streptococcoal diseases
Glomerulonephritis (Type III immunopathology) Rheumatic Fever (Type II)
Discuss child pneumococcal vaccine
7- or newer 13-valent
conjugate
Adult pneumococcal vaccine
23 valent
‘pneumonia vaccine’ -> no resistance to pneumonia
protection against invasive disease
Enterococci diseases
E. faecalis and E. faecium
- normal flora
- emerging antibiotic resistance (VRE)
- urinary tract, surgical wounds, biliary tract, endocarditis
- nosocomial infections
Gram+ cocci
Staphylococci - aureus - epidermidis Streptococci - pyogenes (GAS) - pneumoniae - "viridans" Enterococci - faecalis - faecium
Clostridium characteristics
G+
rod
strict anaerobes
endospore formers
Clostridium family + diseases
C. difficile
- HAcq. diarrhea and colitis
- relatively antibiotic resistant
C. tetani
- tetanus
- blocks inhibitory neurons (spastic paralysis)
C. botulinum
- botulism
- ingestion of preformed toxin
- blocks neuromuscular jcts (flaccid paralysis)
C. perfringens and others
- gangrene/tissue infections (alpha toxin)
- food poisoning (enterotoxin, ingestion of bacteria)
Gram+ rods
Clostridium
- difficile
- botulinum
- tetani
- perfringens
E. coli characteristics
G-
rod
many different strains
E. coli diseases
GI - contaminated food/water - ETEC (enterotoxigenic, traveler's diarrhea) > adherence to intestinal mucosa > toxin disrupting electrolyte balance UTI - endogenous from GI tract - adherence to and interaction with bladder epithelium - beta-hemolytic Abd. infections - escape of colon contents into peritoneal cavity - often assoc. with anaerobic bacteria
Pseudomonas characteristics
G-
rod
Pseudomonas aeruginosa disease
Most of the population is highly resistant
Infections of traumatic injuries, esp BURNS
Chronic lung infections in pts w/CF
HAcq. infections
Intrinsic resistance to many antimicrobials
G- rods
E. coli
Pseudomonas aeruginosa
Klebsiella
Neisseria gonorrhoeae characteristics
G-
(diplo)cocci
Neisseria diseases
gonorrhea
conjunctivities -> blindness
antigenically distinct pili
Scarring and fibrosis from long infection
- possible uterine fibrosis and infertility in females
Neisseria antibiotic resistance
almost always penicillin
reduced sensitivity to cephalosporins
Fluroquinolone resistance highly prevalent
G- cocci
Neisseria gonorrhoeae
Bacteroides characteristics/disease
B. fragilis
anaerobic, but relatively aerotolerant
Small component of normal flora, but frequently found in abd. infections
tissue destructive enzymes, anti-phagocytic capsule, SOD
