Anaerobes Flashcards
Clues to an anaerobic infection
Odor proximity to mucous membranes secondary to animal/human bite gas production growth in anaerobic media
Anaerobic GPC
Peptostreptococcus/ Peptoniphilus
Ruminococcus
Sarcina
Anaerobic GNC
Veillonella
Megashera
Anaerobic GNB
Bacteroides
Prevotella
Fusobacterium
Non-Spore Forming Anaerobic GPB
Actinomyces
Lactobacillus
Propionibacterium
Bifidobacterium
Spore-Forming Anaerobic GPB
Clostridium (has spores and flagella, from water/soil)
Peptostreptococcus
GPC PR/CH Cat- Susceptible to Vano Resistant to Kanamycin Resistant to Colistin
Veillonella
GNC
non-pathogenic, normal flora
Bacteroides fragilis
GNB
NON MOTILE
Indigenous to the oral cavity and gastrointestinal tract
More resistant and other anaerobes
Penicillin resistant strains (beta lac producer), report with beta lac testing
Bile+
Esculin +
CAT +
Indole -
Resistant to Vanco, Kanamycin, and Colistin
Prevotella melaninogenica
(used to be Bacteroides) Short GNB slow grower black/brown pigment NG on BBE
Fusobacterium
GNB Cat- NG on BBE Bile - Esculin -
Fusobacterium nucleatum = Lipase - , long spindle shaped
Fusobacterium necrophorum = round ends, Lipse +
Clostridium perfringens
Gas Gangrene (myonecrosis): liquefaction of muscle with gas formation and signs of toxicity. Intestinal distress ID: boxcar (blunt ends), double beta zone, spore former
Lecithinase + Lipase - Litmus Milk + reverse CAMP + Nagler RXN +
Produces exotoxins
Alpha Toxin = lecithin in cell membrane that destroys host cell
TX: Pen/Tetra
Clostridium botulinum
Botulism
Life threatening neuroparalytic disease caused by heat-labile protein toxin
EXOTOXIN
“Tennis Racket” sub terminal spores
Lechitinase -
Lipase +
subterminal spores
Disease:
Food borne: home-canned goods -> nausea, vomit, paralysis, respiratory failure; neurotoxin binds to synapse and blocks acetylcholine
Wound: from soil containing spores
Infant: Ingestion of spores (honey); SIDS; “floppy baby”
Clostridium tetani
Tetanus
Toxin is absorbed from localized infection
Neurotoxin inhibits release of acetycholine
spastic contractions of voluntary muscles
ID: “drum stick” terminal spore, swarming growth,
Lecithinase -
Lipase -
Anaerobe fluorescence
Use long-wave (366 nm) UV light
Organisms Color of fluorescence Porphyromonas asaccharolitica -Brick red Porphyromonas endodontalis- Brick red Pigmented Prevotella spp.- Brick red Veillonella spp.- Red Eubacterium lentum -Red Clostridium difficile -Chartreuse Clostridium innocuum -Chartreuse Fusobacterium spp.- Chartreuse
Egg Yolk Agar
Lecithinase:
Positive = milky white halo around colony (B.cereus, B.athracis C.perfringens)
Negative = No halo around colony (C.difficile, other Clostridium, B. fragilis)
Lipase:
Positive= iridescent sheen (mother-of-pearl) on colony and surrounding media (Fusobacterium necrophorum)
Negative = No iridescent sheen (C. perfringens, B. fragilis)
obligate anaerobe
will not grow in presence of oxygen (C. botulinum)
microaerophlic
can grow scantily in presence of oxygen (streptococcus)
facultative anaerobe
able to grow in presence or absence of oxygen (e.coli)
microaerotolerant
does not require oxygen for growth but also not killed by limited exposure to room air (PSA)
Potency disks
Gram Positive: Vancomycin S, Colistin R
Gram Negative: Vancomycin R
Exception: Porphyromonas spp. – Vanco S
Clostridium difficile
antibiotic associated diarrhea
pseudomembranous colitis
Lecithinase -
Subterminal spores
Yellow colony on CCFA agar
Clostridium septicum
Lecithinase -
Lipase -
sub terminal spores
“medusa head” colonies
Actinomyces
branching GPB Molar tooth colonies Cat- Indole - "lumpy jaw"
Propionibacterium
cat+
GPB
acne, endocarditis, bacteremia
Bifidobacterium
dog-bone shaped
cat -
Indole -
normal oral/intestinal flora
rarely a pathogen
