Characterization of Colistin-Resistant Escherichia coli Isolated from Diseased Pigs in France.
Characterization of Colistin-Resistant Escherichia coli Isolated from Diseased Pigs in France.
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DOI：
10.3389/fmicb.2017.02278
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发表时间：
2017
影响因子：
5.2
通讯作者：
Kempf I
中科院分区：
文献类型：
--
作者：
Delannoy S;Le Devendec L;Jouy E;Fach P;Drider D;Kempf I
我们研究了2009年至2013年期间从法国病猪中分离的79株耐粘菌素大肠杆菌分离株。我们确定了一些表型和遗传性状，采用肉汤微量稀释法来表征其抗菌药物的敏感性。我们进行了脉冲场凝胶电泳（PFGE），以评估其遗传多样性，并将它们分配到不同的群体。利用高通量实时荧光PCR微阵列筛选毒力遗传标记，并对主要抗性基因进行PCR和测序，以探讨黏菌素的抗性机制。结果表明，分离物分属于几个不同的类群，大多数菌株具有独特的PFGE图谱。超过50%的菌株对磺胺类、甲氧苄啶、四环素、氨苄青霉素或氯霉素也耐药。在79株分离株中的70株中检测到mcr-1基因，其中33株通过接合转移，有时还伴有对磺胺类、甲氧苄啶、四环素、氨苄青霉素、氯霉素、头孢噻肟或庆大霉素的耐药。在有或无mcr-1基因的分离株中检测到蛋白质MgrB、PhoP、PhoQ、PmrB（但未检测到PmrA）的氨基酸序列突变。超过三分之一的分离株携带F18、F4、astA、hlyA、estI、estII、elt、stx 2 e、iha、orfA、orfB、paa、terE、ecs 1763或ureD毒力标记。总之，尽管大多数分离株具有独特的PFGE图谱，但在许多情况下，鉴定了系统发育组、毒力基因和参与粘菌素耐药性的测序基因突变的一些特定组合，表明某些分离株在数年内持续存在。
We studied a collection of 79 colistin-resistant Escherichia coli isolates isolated from diseased pigs in France between 2009 and 2013. We determined a number of phenotypic and genetic characters using broth microdilution to characterize their antimicrobial susceptibility. We performed pulse field gel electrophoresis (PFGE) to assess their genetic diversity and assign them to phylogroups. High-throughput real-time PCR micro-array was used to screen for a selection of genetic markers of virulence, and PCR and sequencing of the main recognized resistance genes allowed us to investigate the mechanisms of colistin resistance. Results showed that isolates belonged to several phylogroups and most had a unique PFGE profile. More than 50% of the isolates were also resistant to sulfonamides, trimethoprim, tetracycline, ampicillin or chloramphenicol. The mcr-1 gene was detected in 70 out of 79 isolates and was transferred by conjugation in 33 of them, sometimes together with resistance to sulfonamides, trimethoprim, tetracycline, ampicillin, chloramphenicol, cefotaxime, or gentamicin. Mutations in the amino-acid sequences of proteins MgrB, PhoP, PhoQ, PmrB, but not PmrA, were detected in isolates with or without the mcr-1 gene. More than one-third of the isolates harbored the F18, F4, astA, hlyA, estI, estII, elt, stx2e, iha, orfA, orfB, paa, terE, ecs1763, or ureD virulence markers. In conclusion, although most isolates had a unique PFGE profile, a few particular combinations of phylogenetic groups, virulence genes and mutations in the sequenced genes involved in colistin resistance were identified on a number of occasions, suggesting the persistence of certain isolates over several years.