Antimicrobial susceptibility of Bacteroides fragilis group organisms in Hong Kong by the tentative EUCAST disc diffusion method.

摘要: Abstract This study used a recently developed EUCAST disc diffusion method to measure the susceptibility of 741 B. fragilis group isolates six antibiotics. Isolates nonsusceptible imipenem and metronidazole by were further investigated E-test. Species identification was obtained matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), PCR assays 16S rRNA sequencing. The most common species (n = 424, including 81 division II 343 I isolates), B. thetaiotaomicron (n = 111), B. ovatus (n = 53) B. vulgatus (n = 46). Overall, following amoxicillin-clavulanate are active agents with over 90% all being susceptible at tentative breakpoints. Susceptibility rates for moxifloxacin (69.5%), piperacillin-tazobactam (58.2%) clindamycin (37.2%) much lower. Metronidazole is only agent against >90% , non- fragilis Bacteroides Parabacteroides isolates. With exception II, 88.0%–98.3% other species. (14.4%–54.3%) (33.3%–80.6%) low across many had no inhibition zone around discs. E-test testing confirmed 8.2% (61/741) 1.6% (12/741) as metronidazole, respectively B. thetaoiotaomicron accounting large share observed resistance both agents. Two imipenem-resistant one metronidazole-resistant B. dorei misidentified MALDI-TOF MS. These data highlights importance anaerobic in clinical laboratories guide therapy.