Characterization and virulence factors distribution of blaCTX-M and mcr-1carrying Escherichia coli isolates from bovine mastitis
Characterization and virulence factors distribution of blaCTX-M and mcr-1carrying Escherichia coli isolates from bovine mastitis
复制标题
牛乳腺炎大肠埃希菌bla(CTX-M)和mcr-1的鉴定及毒力因子分布
DOI：
10.1111/jam.14994
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发表时间：
2021-01-20
影响因子：
4
通讯作者：
Wang, L.
中科院分区：
文献类型：
--
作者：
Shafiq, M.;Huang, J.;Wang, L.
目的了解大肠埃希菌产超广谱β-内酰胺酶（ESBL）及耐粘菌素的情况。材料与方法对535份有乳房炎症状的牛奶样品进行ESBL、粘菌素耐药和不同毒力基因的筛选。药敏试验采用微量稀释法。检测大肠埃希菌ESBL基因（bla（CTX-M）、bla（SHV）和bla（TEM））和大肠杆菌素耐药基因mcr-（1-9）。采用多重PCR方法检测主要bla（CTX-M）群、不同毒力群及毒力基因。结果85%以上的ESBL和耐粘菌素的大肠埃希菌存在多药耐药（MDR）。大肠杆菌分离株。基因型特征显示bla（CTX-M-1）组占优势，观察到的最常见等位基因为bla（CTX-M-28）（38.37%）、bla（CTX-M-14）（17.44%）、bla（CTX-M-66）（13.95%）和bla（CTX-M-55）（10.46%）。在97.89%的菌株中检测到靶毒力基因。序列类型ST 58和ST 410最占优势（2/20 = 20%）。大多数E.结论产ESBL大肠埃希菌与产mcr-1大肠埃希菌之间存在高度相关性。本研究首次报道了产ESBL和mcr-1菌株的遗传多样性，以及大肠杆菌的各种毒力特性。从中国三个不同省份的奶牛临床型乳房炎中分离的大肠杆菌菌株。bla（CTX-M-1）和bla（CTX-M-9）的主要携带者分别为bla（CTX-M-28）和bla（CTX-M-14）等位基因。产ESBL E.大肠杆菌中的mcr-1尤其令人关注。
Aim To investigate the occurrence of ESBL and colistin-resistant E. coli and its genotypic characterization and identification of virulence determinants in cases of bovine mastitis in three provinces of China.Materials and methods Five hundred and thirty-five milk samples presenting mastitis symptoms were screened for the presence of ESBL, colistin-resistant and different virulence genes. Susceptibility testing was identified by the micro-dilution method. Escherichia coli isolates were used to detect ESBL genes (bla(CTX-M), bla(SHV) and bla(TEM)) and colistin-resistant genes mcr-(1-9). Multiplex PCR approach was used for the detection of major bla(CTX-M) groups, different phylogroups and virulence genes. The clonal relationship was then evaluated with MLST, MLSA and PFGE.Results Multi-drug resistance (MDR) was found in more than 85% of ESBL and colistin-resistant E. coli isolates. Genotypic characterization showed a dominance of the bla(CTX-M-1) group, and the most prevalent alleles observed were bla(CTX-M-28) (38.37%), bla(CTX-M-14) (17.44%), bla(CTX-M-66) (13.95%) and bla(CTX-M-55) (10.46%). The targeted virulence genes were detected in 97.89% of isolates. Sequence types ST58 and ST410 were the most predominant (2/20 = 20%). The majority of the E. coli isolates carrying ESBL and mcr-1 were clonally unrelated.Conclusion High level of association was observed between ESBL-producing and COL-resistance in E. coli of bovine mastitis.Significance and Impact of the Study To the best of our knowledge, this is the first report which shows the genetic diversity of ESBL and mcr-1, and various virulent features of E. coli strains isolated from bovine clinical mastitis in three different provinces of China. The major carriers of the bla(CTX-M-1) and bla(CTX-M-9) were bla(CTX-M-28) and bla(CTX-M-14) alleles respectively. The association of ESBL-producing E. coli with mcr-1 is of particular concern.