Todorović Dalibor, Velhner Maja, Grego Edita, Vidanović Dejan, Milanov Dubravka, Krnjaić Dejan, Kehrenberg Corinna
1 Scientific Veterinary Institute "Novi Sad," Novi Sad, Serbia .
2 Public Health Institute of Serbia , "Dr Milan Jovanović Batut," Belgrade, Serbia .
Microb Drug Resist. 2018 Jan/Feb;24(1):95-103. doi: 10.1089/mdr.2017.0016. Epub 2017 May 18.
The aim of the study was to characterize multidrug-resistant (MDR) Escherichia coli isolates collected in Serbia from bovine clinical mastitis cases and diseased pigs, mainly with molecular methods. A total of 48 E. coli isolates was collected during the years 2013-2014, of which 22 were MDR and were included in further analysis. Phylogenetic typing showed that 17 isolates belonged to group A, while two isolates were classified in group B1 and a single one in group D. All isolates showed unique macrorestriction patterns. Phenotypic susceptibility testing revealed resistances of the isolates against up to 13 antimicrobial agents, including resistance to fluoroquinolones. A wide variety of resistance genes was detected by PCR amplification and sequencing of amplicons. Sequence analysis of the quinolone resistance determining regions of topoisomerase genes revealed mutations in gyrA, parC, and/or parE. Plasmid-mediated quinolone resistance genes were detected in two porcine (aac-6'-Ib-cr and qnrS, respectively) isolates and a single bovine (aac-6'-Ib-cr) isolate. Resistance genes were found to be located on conjugative plasmids in 16 cases, many of which conferred a multidrug resistance phenotype. In conclusion, the plentitude of resistance genes located on conjugative plasmids and integrons in E. coli from cows and pigs in Vojvodina, Serbia, pose a high risk for horizontal gene transfer in bacteria from livestock husbandry.
本研究的目的是主要通过分子方法对在塞尔维亚收集的来自牛临床乳腺炎病例和患病猪的多重耐药性（MDR）大肠杆菌分离株进行特征分析。2013年至2014年期间共收集了48株大肠杆菌分离株，其中22株为多重耐药株，并纳入进一步分析。系统发育分型显示，17株分离株属于A组，2株属于B1组，1株属于D组。所有分离株均呈现独特的宏观限制性图谱。表型药敏试验显示，这些分离株对多达13种抗菌药物耐药，包括对氟喹诺酮类耐药。通过PCR扩增和扩增子测序检测到多种耐药基因。对拓扑异构酶基因的喹诺酮耐药决定区进行序列分析，发现gyrA、parC和/或parE发生了突变。在2株猪源分离株（分别为aac-6'-Ib-cr和qnrS）和1株牛源分离株（aac-6'-Ib-cr）中检测到质粒介导的喹诺酮耐药基因。在16例中发现耐药基因位于接合质粒上，其中许多赋予多重耐药表型。总之，塞尔维亚伏伊伏丁那地区牛和猪的大肠杆菌中位于接合质粒和整合子上的大量耐药基因，对畜牧细菌中的水平基因转移构成了高风险。
