EVALUATION OF THE ETEST FOR ANTIMICROBIAL SPECTRUM AND POTENCY DETERMINATIONS OF ANAEROBES ASSOCIATED WITH BACTERIAL VAGINOSIS AND PERITONITIS

One hundred ninety-seven anaerobic organisms (24 Gardnerella vaginalis , 16 Mobiluncus spp., 19 Peptostreptococcus spp., 20 Lactobacillus spp ., 20 Prevotella bivia/disiens, 81 Bacteroides fragilis group, 12 Clos tridium spp., and five Fusobacterium spp.) were processed by the Etest (AB Biodisk, Solna, Sweden) and a reference (Brucella blood agar) met hod against 10 antimicrobial agents. For the bacterial vaginosis-assoc iated pathogens, the Etest was more reproducible and correlated accept ably with the reference agar test: within +/-1 log(2) dilution for 74. 4% of Mobiluncus spp, to 96.0% for Peptostreptococcus spp. (all organi sms, 83.4%). The quantitative correlation +/-2 log(2) dilution steps b etween test results was 94.3%. Results with B. fragilis group strains demonstrated 97.3% correlation (+/-2 log(2) dilution) with a trend tow ard slightly lower Etest minimum inhibitory concentrations for ampicil lin-sulbactam, cefotaxime, imipenem, and clindamycin. The absolute qua litative interpretive agreement between Etest and the reference agar d ilution method results was 94.4%, with only a 0.4% false-susceptible e rror rate. The Etest appears to be a very practical, quantitatively ac curate, alternative procedure for clinical microbiology laboratories r outinely testing the susceptibilities of anaerobes and, by these prese nted data, organisms associated with female tract infections.