GN anaerobes

where are GN anaerobes found?

* resp: prevotella, porphyro, fuso
* GI: bacteroides
* GU: fuso, prevotella, bacteroides

anaerobic infections

* endogenous: trauma or accidental contact with other sites
* surgery, punctures, aspiration of oral secretions to lungs
* exogenous is bite wounds
* local or spreads
* abscess, bacteremia, peritonitis, pneumonia

bacteroides

* most commonly isolated anaerobic GNR
* abscess formation = hallmark
* polymicrobic infections in abd, pelvis, perirectal skin, solid organs

bacteroides virulence factors

* capsule
* pili/fimbriae
* enzymes to spread/digest tissue and survive prolonged oxygen exposure

b. frag group

* b. fragilis, distasonis, ovatus, thetaiotamicron, vulgatus
* bile resistant: black on BBE
* infections: intra abd, perirectal, decubitus ulcers, bacteremia
* **R to penicillin** (beta lactamase producer)
* enterotoxigenic = diarrhea

b. ureolyticus group

* bile sensitive
* S to kanamycin
* campylobacter spp
* bilophila wadsworthia (resistant, fish eyes)
* sutterella (resistant)
* all nitrate pos

b. frag presumptive ID

* anaBAP/LKV: large, convex with chartreuse fluoro
* GNR
* BBE: large, convex, gray black
* R to K and V
* indole not performed

esculin hydrolysis bacteroides frag group

b. uniformis neg (others pos)

indole - bacteroides frag group

* pos: b. ovatus, thetaiotamicron, uniformis
* neg: others

cat 15% - bacteroides frag group

* pos: b. fragilis, distasonis, ovatus, thetaiotamicron
* V: uniformis
* neg: others

presumptive ID of b. ureolyticus

* anaBAP: translucent, pitting
* no LKV: S to kana
* neg 15% catalase, indole
* tiny GNR/ccb
* no BBE

bilophila wadsworthia presumptive ID

* anaBAP: tiny translucent
* no LKV: S to K and V
* strong cat pos 15%
* BBE: fish eye colonies (black centers)
* neg indole

esculin hydrolysis b. ureolyticus group

b. wadsworthia pos, others neg

oxidase bacteroides ureolyticus group

c. ureolyticus pos, others neg

cat 15% - b. ureolyticus group

pos: b. wadworthia

V: c. ureolyticus

neg: others

urease - b. ureolyticus group

pos: c. ureolyticus

V: b. wadsworthia

neg: others

prevotella spp

* normal oral, GU tract
* all clinically relevant species are bile sensitive

pigmented prevotella species

* p. denticola, intermedia, loescheii, melanginogenica
* oral, dental, bite infections
* head, neck, LRT infections

nonpigmented prevotella species

* p. bivia, disiens
* female genital tract infections and soft tissue infections

prevotella presumptive ID

* anaBAP, LKV: small translucent/opaque colonies
* brown black pigment
* fluoro brick red
* tiny GN ccb
* no growth BBE
* indole:
* intermedia pos, others neg

colistin - prevotella

p. bivia R, others V

lipase - prevotella

p. intermedia, loescheii pos; others neg

porphyromonas spp

* common oral flora
* p. endodontalis, gingivalis
* aggressive periodontitis; heart disease, atherosclerosis, diabetes
* biofilms plaques
* root canals, sinusitis
* p. asaccharolytica: GI/GU tracts

porphyromonas presumptive ID

* anaBAP: small translucent/opaque
* brown/black pigment
* fluoro brick red (except gingivalis)
* no LKV: S to V
* tiny GN ccb
* no BBE
* indole pos

f. nucleatum

* most commonly isolated fuso
* oral cavity, URT, GU, GI tracts
* sole pathogen in pleuropulmonary

f. necrophorum

* URT infections following pharyngotonsillitis, IM, bacterial pharyngitis
* virulence factors: endotoxin, leucocidin, hemolysin, hemagglutinin
* cause lemierre’s syndrome and vincent’s angina
* large pleomorphic cells
* pos lipase

lemeirre’s syndrome

* after pharyngitis
* endotoxins spread bacteria into jugular vein
* inflammation, plt aggregation, clot formation in vein
* persistent fever, acute pharyngitis, sepsis, neck tenderness, swelling

vincent’s angina

* acute necrotizing ulcerative gingivitis, trench mouth
* bad breath, blunting of interdental papilla, necrotic sloughing of gingiva
* very painful, bleeding

f. mortiferum, varium

* found in polymicrobial intra abd infections
* mortiferum: bizarre, round bodies, neg indole
* varium: large, rounded ends

f. nucleatum presumptive ID

* anaBAP: opalescent bread crumb w chartreuse fluoro
* no growth on LKV
* fusiform thin pointed GNR
* no growth BBE
* indole pos

bile resistance - fusobacterium

R: mortiferum, varium

S: nucleatum, necrophorum

veillonella

* normal oral, GU, resp, GI tract flora
* rare sole pathogen in meningitis, joints, pleuropulmonary, bacteremia, endocarditis

veillonella presumptive ID

* anaBAP/LKV: small transparent/opaque colonies
* red fluoro that fades rapidly
* tiny GN dcc
* no growth BBE
* neg indole

vanc susceptible GN

porphyromonas

kanamycin susceptible

bacteroides (not frag), bilophila, fuso, veillonella

colistin susceptible

bacteroides (not frag), bilophila, fuso, veillonella, prevotella