Emergence of Carbapenem Resistance in Bacteroides fragilis in China.

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Emergence of Carbapenem Resistance in Bacteroides fragilis in China.

Int J Antimicrob Agents. 2019 Mar 01;:

Authors: Gao Q, Wu S, Xu T, Zhao X, Huang H, Hu F

Abstract
The antimicrobial resistance crisis makes it critically important for laboratories to closely monitor trends and mechanisms of emerging antimicrobial resistance in clinical isolates. Bacteroides fragilis is an anaerobic pathogen that causes several serious infections and is increasingly resistant to antimicrobials. However, data from China regarding antimicrobial resistance in B. fragilis are limited. In this work, we investigated the mechanism underlying carbapenem resistance in 44 B. fragilis isolates collected from a Chinese hospital. Among the 44 isolates, 18.2%, 29.5%, 22.7%, 100%, 100%, 29.5%, 15.9%, 81.8%, 88.6%, and 47.7% were resistant to imipenem, meropenem, ertapenem, penicillin, ampicillin, amoxicillin-clavulanic acid, piperacillin-tazobactam, clindamycin, tetracycline, and moxifloxacin, respectively. None of the isolates were resistant to metronidazole, cefoxitin or chloramphenicol. A chromosome-located gene (cfiA) encoding a metallo-beta-lactamase was identified in 16 isolates (36.4%). A conserved insertion sequence of IS1187 or IS613 was upstream of cfiA in 8 isolates with high-levels of carbapenem resistance. The insertion sequences were associated with an increase of carbapenem resistance in B. fragilis by upregulating the expression of cfiA, as indicated by qRT-PCR. This is the first study to describe a mechanism of carbapenem resistance in B. fragilis in mainland China.

PMID: 30831235 [PubMed - as supplied by publisher]