General Bacteriology Flashcards
Ziehl-Neelsen/Kinyoun/Fite stains
mycobacteria stain pink/red
- ZN/Kinyoun = most commonly used
- Fite often used for M leprae (b/c leprae often decolorized by ZN/K). Also for Nocardia
Warthin-Starry stain (positive test, what it tests for)
dark brown/black against a yellow/gold background
- spirochetes (treponema, borrelia, leptospira)
- H pylori
- Bartonella henselae (clue for bacillary angiomatosis or bacillary peliosis hepatis)
Rapidly growing NTM
abscessus group
chelonae
fortuitum group
Streptomyces
Nocardia
Members of aerobic actinomycetes (and micro characteristics)
- nocardia
- rhodococcus
- streptomyces
mAF stain+ (d/t presence of mycolic acids in cell wall)
branching GPR
typically isolated in fungal cx (as opp to standard bacterial cx) d/t slow growth
Antimicrobials w/ poor CNS penetration
- any abx given PO
- beta-lactamase inhibitors
- 1-2nd gen cephs
- cephamycins
- clinda
- FQ
- macrolides
- tetracyclines
Vanc-R Bacteria
- most GNs
- Clostridium innocuum
- Enterococcus gallinarum and casseliflavus (d/t chromosomal vanC)
- Erysipelothrix rhusiopathiae
- Lactobacillus
- Leuconostoc
- Pediococcus
- Weissella
Colistin-R Bacteria
- most GPs
- burkholderia
- inguilinus limosus
- N gonorrhea, N meningitidis
- Pandoraea
- Proteae
- Serratia
SPICE Organisms (what are they and what are they resistant to?)
- Serratia spp
- PSAR
- Indole+ proteae (P vulgaris, Providencia spp, Morganella)
- Citrobacter freundii complex
- Enterobacter
- chromosomal AmpC beta-lactamase –> results in R to penicillins (except piperacillin), amp/sulbactam, amox/clav, 1-2nd gen cephalosporins, and cephamycins
- may become de-repressed on exposure to b-lactams –> R to 3rd gen cephs, zosyn, and erta
Intrinsic R of listeria
cephalosporins
Intrinsic R of Proteae
- colistin
- nitrofurantoin
- tetracyclines
- May have elevated MICs to imipenem
*Refer to SPICE organisms
Intrinsic R of Kleb (not aerogenes)
ampicillin
Intrinsic R of Citrobacter koseri
amp
piperacillin
ticarcillin
Intrinsic R of Burkholderia cepacia complex
- all penicillins and penicillin derivatives
- 1-4 gen cephs (except ceftaz)
- cephamycins
- erta, imi
- aminoglycosides
- colistin
- fosfomycin
- aztreonam
Intrinsic R of non-glucose-fermenting (nonfermenters) GNR
ertapenem
Intrinsic R of aerobic GNR
clinda
vancomycin
a/w poultry
campy
salmonella
a/w oysters
vibrio vulnificus
a/w gravy
C perfringens
a/w eggs
salmonella
a/w chitterlings
yersinia enterocolitica
Reference AST Methods for
Aerobic bacteria
Anaerobic bacteria
Aerobic - Kirby Bauer disk diffusion and broth microdilution (eg Vitek)
Anaerobic - agar dilution
a/w rodents
- leptospira (rodent urine, think water and rustic cabins)
- salmonella
- spirillum minus
- strep moniliformis (rat bite fever)
- Yersinia pestis
a/w leeches
aeromonas
a/w dogs
campy
leptospira
pasteurella
staph intermedius/pseudointermedius
a/w fish
- E rhusiopathiae
- Streptococcus iniae
- Vibrio
a/w farm animals
- bacillus anthracis
- brucella
- coxiella
- campy
- Shiga-producing E coli
- Erysipelothrix rhusiopathiae
- Leptospira
- Salmonella
a/w cats
- bartonella henselae
- pastuerella
a/w birds
chlamydia/chlamydophila psittaci
tiny GNRs
oxidase-, weak catalase+
growth on chocolate only
N America
Europe
Asia
hunters (rabbits), muskrats, prarie dogs
ticks, deer fly bites
mowing over rabbit’s nest
Francisella tularensis
GNRs, colonies w/ “cracked/dry earth” appearance
musty odor
oxidase +, colistin R
Tropics (esp SE Asia and Australia)
agricultural workers
persons w/ open skin wounds/DM/CKD
Burkholderia pseudomallei (Melioidosis)
GNR coccobacilli
slow growth - variable on MacConkey agar
oxidase variable, colistin R
C and S America
ME, Asia
Africa
vets, horse caretakers, abattoir workers
Burkholderia mallei
tiny GNR, oxidase+, urease+
May be mis-ID as Ochrobactrum on MALDI
Mexico, S and C America
Caribbean
Mediterranean basin, E Europe, ME
eating undercooked meats, raw dairy
vets
abattoir workers
hunters
Brucella
big, boxy GPR (often chains)
catalase +
Nonmotile
WW
persons who work w/ animal products
livestock producers
vets
Bacillus anthracis
Bacillus cereus
GNR
beta-hemolytic
oxidase negative
indole positive
lactose fermenting
E coli
GNR
beta-hemolytic
metallic sheen
Green pigment on MacConkey
PSAR
MacConkey Agar/Lactose-fermentation (What grows, what only grows on chocolate, and what doesn’t grow)
Nonfastidious GNR
Enterobacterales
Most non-fermenters
What doesn’t
- GP organisms (may see some bacillus spp though)
- Fastidious GNs: Brucella, HACEK, Francisella, Moraxella, Neisseria, Pasteurella
Chocolate Agar (What grows, what only grows on chocolate, and what doesn’t grow)
**almost all organisms grow on this media, including fastidious organisms
Only grows here
- Haemophilus
- Some aggregatibacter and some N gonorrhea
- Francisella
- Granulocatella/Abiotrophia
What Doesn’t
- some corynebacterium grow better on blood
- organisms that don’t grow on routine bacterial cultures
Important Pathogens in Bite Wounds
- anaerobic oral flora
- Eikenella
- Pasteurella
- staph intermedius/pseudointermedius
- Strep anginosus group
When you here this…
tiny, gram-negative rods
brucella
francisella
When you here this…
Spores on gram stain
- bacillus spp
- related genera: paenibacillus, lysinibacillus
- clostridium
When you hear this…
seagull-shaped/gull wings
campy
When you hear this…
lancet shaped
S pneumoniae
When you here this…
gram stain - big and boxy
bacillus
clostridium
When you here this…
GN diplococci - respiratory
M catarrhalis
When you here this…
GN diplococci - genital, urine, joint fluid
N gonorrhea
When you hear this…
Gram-negative diplococci in the CSF
N meningitidis
Organisms a/w GI cancer
Streptococcus (formerly bovis group):
- gallolyticus
- infantarius
- alacyolyticus
- lutetiensis
- equinous
Clostridium septicum (also heme malignancy)
The most common gram-variable bacteria
- bacillus spp
- clostridium spp
- acinetobacter spp
- streptococcus pneumoniae
Gram negative rods - curved
- campylobacter
- helicobacter
- vibrio (comma-shaped)
Gram-negative rods - fusiform
- fusobacterium
- capnocytophaga
Gram negative coccobacilli
- haemophilus
- acinetobacter (may be gram-variable)
- aggregatibacter
- moraxella
- pasteurella
- bacteroides
- francisella tularensis
- brucella
Gram-variable rods
- bacillus
- clostridium
- gardnerella vaginalis
- leptotrichia
Branching, filamentous GPR
- nocardia
- streptomyces
- gordonia
- tsukamurella
GPR
- bacillus, clostridium (may be big/box, may have spores)
- listeria (may appear coccobacillary)
- lactobacillus
- eggerthella
GPC in pairs/chains
- VGS
- Beta-hemolytic strep (eg S pyogenes)
- Enterococcus
- Abiotrophia, Granulicatella (prev NVS)
