Molecular characterization of florfenicol and oxazolidinone resistance in Enterococcus isolates from animals in China

作者：Pingping Li, Mengdi Gao, Chunlin Feng, Tielun Yan, Zhiqiong Sheng, Weina Shi, Shuang Liu, Lei Zhang, Anqi Li, Junwan Lu, Xi Lin, Kewei Li, Teng Xu, Qiyu Bao, Caixia Sun · 发表于：Frontiers in Microbiology · 年份：2022 · DOI：10.3389/fmicb.2022.811692 · 被引用次数：11 · 研究领域：Antimicrobial Resistance in Staphylococcus、Bacterial Identification and Susceptibility Testing、Antibiotic Resistance in Bacteria

Florfenicol is widely used for the treatment of bacterial infections in domestic animals. The aim of this study was to analyze the molecular mechanisms of florfenicol and oxazolidinone resistance in Enterococcus isolates from anal feces of domestic animals. The minimum inhibitory concentration (MIC) levels were determined by the agar dilution method. Polymerase chain reaction (PCR) was performed to analyze the distribution of the resistance genes. Whole-genome sequencing and comparative plasmid analysis was conducted to analyze the resistance gene environment. A total of 351 non-duplicated enteric strains were obtained. Among these isolates, 22 Enterococcus isolates, including 19 Enterococcus. faecium and 3 Enterococcus. faecalis , were further studied. 31 florfenicol resistance genes (13 fexA , 3 fexB , 12 optrA, and 3 poxtA genes) were identified in 15 of the 19 E. faecium isolates, and no florfenicol or oxazolidinone resistance genes were identified in 3 E. faecalis isolates. Whole-genome sequencing of E. faecium P47, which had all four florfenicol and oxazolidinone resistance genes and high MIC levels for both florfenicol (256 mg/L) and linezolid (8 mg/L), revealed that it contained a chromosome and 3 plasmids (pP47-27, pP47-61, and pP47-180). The four florfenicol and oxazolidinone resistance genes were all related to the insertion sequences IS 1216 and located on two smaller plasmids. The genes fexB and poxtA encoded in pP47-27, while fexA and optrA encoded in the conjug...