Data_Sheet_1_Identification of novel Tet(X6)-Tet(X2) recombinant variant in Elizabethkingia meningoseptica from a bullfrog farm and downstream river in China.pdf

IntroductionThe dissemination of strains producing tetracyclines monooxygenase Tet(X) from breeding farms to the natural environment poses a potential threat to public health.MethodsAntimicrobial susceptibility testing and WGS were performed to identify resistance phenotypes and genotypes. Cloning experiments, sequence alignment, and homology modeling were used to characterize the function and formation mechanisms of the recombinant variant. The mobilization potential of Tet(X) was assessed by collinearity analysis, conjugation experiments, and phylogenetic analysis.ResultsThree tet(X)-producing Elizabethkingia meningoseptica strains were isolated from bullfrog breeding ponds, the sewage outlet, and downstream river in Zhejiang Province, China. These strains carry a novel Tet(X) variant, differing from Tet(X6) by seven residues, and possess the ability to degrade tetracyclines. Interestingly, the novel Tet(X) is a recombinant variant formed by homologous recombination of Tet(X6) and the C-terminal of Tet(X2). Further analysis revealed that Tet(X6) formed several Tet(X) variants, including Tet(X5), through homologous recombination. The novel tet(X) gene is located on a circularizable integrative and conjugative element (ICEEmeChn3), with ISwz1 participating in the recombination of its multi-drug resistance region, potentially facilitating the mobilization and recombination of tet(X) in early hosts. These three strains were clonally transmitted and shared a close genetic relationship (SNP

引言：从养殖场向自然环境传播产生四环素单加氧酶Tet(X)的菌株，对公共卫生构成了潜在的威胁。方法：通过抗菌敏感性测试和全基因组测序来识别耐药表型和基因型。通过克隆实验、序列比对和同源性建模来表征重组变种的生物学功能和形成机制。通过相关性分析、接合实验和系统发育分析来评估Tet(X)的移动潜力。结果：从浙江省的牛蛙养殖池塘、污水出口和下游河流中分离出三种产生tet(X)的Elizabethkingia meningoseptica菌株。这些菌株携带一种新的Tet(X)变种，与Tet(X6)相比有七个残基的差异，并且具有降解四环素的能力。有趣的是，这种新的Tet(X)是一种由Tet(X6)和Tet(X2)的C端通过同源重组形成的重组变种。进一步分析表明，Tet(X6)通过同源重组形成了包括Tet(X5)在内的多个Tet(X)变种。新的tet(x)基因位于可环化的整合和接合元件(ICEEmeChn3)上，其中ISwz1参与其多药耐药区域的重组，可能有助于早期宿主中tet(X)的传播和重组。这三种菌株通过克隆传播，并具有密切的遗传关系（SNP）