ORGANISMS ISOLATED FROM DOGS AND CATS WITH ANAEROBIC INFECTIONS AND SUSCEPTIBILITY TO SELECTED ANTIMICROBIAL AGENTS

Objective--To determine the prevalence of obligate anaerobic bacteria in bacterial infections in dogs and cats and susceptibility to selecte d antimicrobial agents. Design--Case series. Sample Population--Specim ens from 1,267 dogs and 243 cats. Procedure--Standard anaerobic and ae robic bacterial culture methods were used. Anaerobic isolates were tes ted for susceptibility to selected antimicrobial agents. Results--Obli gate anaerobic bacteria were isolated from 199 (15.7%) and 69 (28.4%) specimens obtained from dogs and cats, respectively. More than half of the specimens that contained obligate anaerobic bacteria were from dr aining tracts (exclusively dogs), pleural fluid, abscesses, bones, the respiratory tract, or the abdominal cavity. The most commonly isolate d obligate anaerobic bacteria (approx 70% of all isolates) were Bacter oides spp, Peptostreptococcus spp. Fusobacterium spp, and Porphyromona s spp. Eighty percent of the specimens that contained obligate anaerob ic bacteria also contained facultative anaerobic or aerobic organisms. The organisms most commonly isolated in association with obligate ana erobic bacteria were members of the family Enterobacteriaceae (Escheri chia coli was the most common), Pasteurella spp, and Staphylococcus in termedius. Ninety-seven obligate anaerobic isolates were tested for su sceptibility to ampicillin, amoxicillin-clavulanic acid, chloramphenic ol, clindamycin, and metronidazole . All were susceptible to amoxicill in-clavulanic acid and chloramphenicol, and most were susceptible to m etronidazole. Only 71% of the Bacteroides isolates were susceptible to ampicillin, and only 83% were susceptible to clindamycin. Only 80% of the Clostridium isolates were susceptible to clindamycin, but all wer e susceptible to ampicillin. Clinical Implications--Data on sites and conditions from which anaerobic bacteria are commonly isolated, along with results of susceptibility testing, may be useful in designing ant imicrobial treatment regimens.