chapter 32 bug info Flashcards
strep pneumoniae
GP diplococci aligned end to end
most common cause of bacterial pneumonia
also meningitis and otitis
in normal through flora
group A strep (streptococcus pyogenes)
beta-hemolytic - so compete hemolysis on blood agar
GP cocci in chains
phyaryngitis, wound infections,
rheumatic fever and acute glomerulonephritis
very sensitive to penicillin G!
group B strep (streptococcus agalactiae)
usually beta hemolytic
mostly penicillin G sensitive
normally in female genital tract
neontal septicemia and meningitis
viridans streptococci
GP in chains or pairs
normal oral cavity
most common cause of subacute bacterial endocarditis on previously damaged valves
penicillin may be sufficient
peptostreptococcus
obligate anaerobes GP in clumps or chains
very sensitive to penicillin G
often in normal oral and fecal flora
anaerobic infections:
brain abscesses
liver abscesses
enterococcus fecalis
GP coccus in pairs and chains
normal fecal flora
UTIs (5-10%)
endocarditis (#2 for SBE)
mostly penicillin resistant, cephalosporin resistant
can use ampicillin, vancomycin
some (e. faecium vanco resistant)
staph aureus
coagulase positive
GP singly, pairs, or grape-like clusters
furuncles cellulitis endocarditis meningitis minor cause of pneumonia
sensitive to methicillin, oxacillin, mafcillin except MRSA
toxins can result in food poisoning and TSS
staph epidermidis
coag negative
GP singly, in pairs and clumps
normal skin flora
most resistant to methicillin, oxacillin
artificial implants
IV catheters
bancomycin sensitive
staph saprophyticus
uncomplicated UTI
coag negative
neisseria meningitis
GNC side to side
grows best with CO2
menigitis and meningococcemia
penicillin G sensitive
give ABX prophylaxis to close contacts - rifampin, ceftriaxone
neisseria gonorrhoeae
GNC (diplo)
urethritis, PID
needs CO2 for growth
moraxella
GNC
pneumonia in COPD and elderly
suppurative otits
many are amoxicillin resistant
Hemophilus influenzae
GNR
chocolate agar
meningitis epiglottits (bronchitis) otitis pneumonia COPD exacerbations
ceftriaxone
enterobacteriaceae
GNR, grow aerobically on simple media
ferment glucose
grow under anaerobic conditions too
not penicillin sensitive
E. coli
enterobacteriaceae
GNR
UTI (most common cause) bacteremia meningitis in neonates sepsis in hospitalized pts pneumonia in hosptialized pts
in normal large intestine
usually ampicillin and cephalothin sensitive
klesiella
enterobacteriacae
GNR
pneumonia
UTI
pneumonia in hosp pts
cephalothin sensitive
enterobacter
enterobacteriaceae
GNR
pneumonia in hosp pts
salmonella typhi
enterobacteriaceae
GNR
typhoid fever
non-typhi salmonella
enterobacteriaceae
GNR
self-limiting gastroenteritis
carriage in domestic animals (ingestion of eggs, poultry, pork, etc)
dx with positive stool culture
shigella
enterobacteriaceae
GNR
dysentery - blood and pus in stool
foodborne outbreaks only if contaminated with human feces
bacteria viable in foods for short periods only
proteus (and morganella)
enterobacteriaceae
GNR
UTs
minor normal fecal flora member
mirabilis is ampicillin sensitive but others mreo resistant
serratia (and citrobacter)
enterobacteriaceae
GNR
fairly ABX resistant
pneumonia in hospitalized pts
no GI diseases
pseudomonas aeruginosa
aerobic GNR
obligate aerobe
bacteremia
UTI
burn infections
pneumonia in CF and hospitalized Ca pts
tobramycin and gentamicin sensitive
ceftrazidime and fourth gen cephalosporins (anti-pseudomonal)
campylobacter
GNR, slightly curved
Dx via isolation from pt stools
microaerophilic (needs o2 but at lower concentration than normal air)
gastroenteritis
vibrio cholera
aerobic GNR, slightly curved
Dx via isolation from pt stools, needs special media
cholera
vibrio parahaemolyticus
aerobic GNR, slightly curved
Dx via isolation from pt stools, needs special media
less severe than cholera, watery diarrhea
from contaminated seafood
yersinia enterocolitica
aerobic GNR
Dx via isolation from pt stools
infrequent GI disease resembling salmonella
to humans from feces of domesticated animals
acinetobacter
GNR, coccobacillus
obligate aerobe
opportunistic
respiratory therapy equipment
indwelling catheters
sepsis, pneumonia, UTI in hospitalized pts
bacteroides
prevotella
GNR
anaerobe
normal ins tine and mouth
fragilis resisitant to penicillin G and ceph 1
legionella pneumophila
unusual GNR
hard to grow
legionnaires disease (pneumonia)
facultative intracellular - azithromycin or erythromycin since they penetrate host cells
bordatella pertussis
small GNR
not easily cultured
whooping cough
acellualr vaccine
erythromycin
mycoplasma
noxell walls
atypical pneumonia
penicillin resistant
use tetracycline or erythromycin
chlamydia trachomatis
obligate intracellular
must be grown in tissues
non gonococcal urethritis
eye infections
pneumonia in infants - macrolides (azithromycin)
dx with gene-probe
tx with doxycycline or azithromycin (penetrates cell walls)
mycobacterium tuberculosis
acid-fast rod
TB
need six weeks to grow in lab
clostridium difficile
GPR
frequently form spores
obligate anaerobes
ABX associated diarrhea
pseudomembranous colitis (most severe diarrhea)
elderly more at risk
makes Toxin A = enterotoxic, B = cytotoxic
stop ABX
can give oral vancomycin (not absorbed from GI tract) or metronidazole if severe
clostridium tetani
GPR
frequently form spores
obligate anaerobes
clostridium botulinum
GPR
frequently form spores
obligate anaerobes
clostridium perfringens
GPR
frequently form spores
obligate anaerobes
gas gangrene
bacillus anthracis
aerobic GPR
form very resistant spores
bacillus cereus
aerobic GPR
very resistant spores
food poisoning, especially in reheated foods (fried rice)
spores resist heating
listeria monocytogenes
GPR
aerobic
not spore forming
transmitted via dairy and meat
food poisoning
occasionally meningitis, esp in elderly
fetal death if transmitted to fetus
farm animal fecal exposure
lactobacillus
non-pathogenic GPR without spores
fermented dairy products (yogurt)
some in intestine and vaginal tract
staphlococcus GI disease characteristics
2-4 hour incubation
vomiting, 30% diarrhea, prostration
bacterium is heat sensitive, toxin is resistant
pastries preserved meats tuna salad potato salad mayo
contaminated by humans
salmonella GI disease characteristics
8-48 hr incubation
often vomiting
diarrhea and pyrexia
bacterium and toxin are heat sensitive
poultry, pork, other unpreserved meats, eggs, salads
spread by people, meat animals, pork, poultry, eggs
C. perfringens GI disease characteristics
6-24 hour incubation period, usually 8-12 hrs
rarely vomiting
diarrhea
heat resistant spores
large roasts or cooked beef, other meats
spread in raw beef, feces, soil?
c. botulinum GI disease characteristics
resistant spores, but toxin is heat sensitive
uncooked home canned veggies, anaerobic packages of fish
spread in soil, lakes, fish, vegetation
