Background

A plasmid-mediated mechanism of bacterial resistance to polymyxin is a serious threat to public health worldwide. The present study aimed to determine the occurrence of plasmid-mediated colistin resistance genes and to conduct the molecular characterization of mcr-positive Escherichia coli strains isolated from Polish poultry.

Methods

In this study, 318 E. coli strains were characterized by the prevalence of mcr1–mcr5 genes, antimicrobial susceptibility testing by minimal inhibitory concentration method, the presence of antimicrobial resistance genes was screened by PCR, and the biofilm formation ability was tested using the crystal violet staining method. Genetic relatedness of mcr-1-positive E. coli strains was evaluated by multilocus sequence typing method.

Results

Among the 318 E. coli isolates, 17 (5.35%) harbored the mcr-1 gene. High antimicrobial resistance rates were observed for ampicillin (100%), tetracycline (88.24%), and chloramphenicol (82.35%). All mcr-1-positive E. coli strains were multidrug-resistant, and as many as 88.24% of the isolates contained the bla_TEM gene, tetracycline (tetA and tetB), and sulfonamide (sul1, sul2, and sul3) resistance genes. Additionally, 41.18% of multidrug-resistant, mcr-1-positive E. coli isolates were moderate biofilm producers, while the rest of the strains showed weak biofilm production. Nine different sequence types were identified, and the dominant ST was ST93 (29.41%), followed by ST117 (17.65%), ST156 (11.76%), ST 8979 (11.76%), ST744 (5.88%), and ST10 (5.88%). Moreover, the new ST was identified in this study.

Conclusions

Our results showed a low occurrence of mcr-1-positive E. coli strains isolated from Polish poultry; however, all the isolated strains were resistant to multiple antimicrobial agents and were able to form biofilms at low or medium level.

中文翻译：

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从波兰家禽中分离出的 mcr-1 阳性多重耐药大肠杆菌 ST93、ST117、ST156、ST10 和 ST744 的表型和基因型特征

背景

质粒介导的细菌对多粘菌素的抗性机制对全世界的公共卫生构成严重威胁。本研究旨在确定质粒介导的粘菌素抗性基因的出现，并对从波兰家禽中分离的mcr阳性大肠杆菌菌株进行分子表征。

方法

本研究对 318株大肠杆菌进行了mcr1-mcr5基因检测、最小抑菌浓度法药敏试验、PCR 筛选是否存在耐药基因、生物膜形成能力检测等指标。紫罗兰染色法。通过多位点序列分型方法评估mcr-1阳性大肠杆菌菌株的遗传相关性。

结果

在 318株大肠杆菌中，17 株（5.35%）含有mcr-1基因。氨苄青霉素 (100%)、四环素 (88.24%) 和氯霉素 (82.35%) 的抗菌素耐药率很高。所有mcr-1阳性大肠杆菌菌株均具有多重耐药性，多达 88.24% 的分离株含有bla _TEM基因、四环素（tetA和tetB）和磺胺（sul1、sul2和sul3）耐药基因。此外，41.18% 的耐多药、mcr-1阳性大肠杆菌分离株是温和的生物膜生产者，而其余菌株则表现出弱的生物膜生产。鉴定出9种不同的序列类型，占优势的ST为ST93（29.41%），其次是ST117（17.65%）、ST156（11.76%）、ST 8979（11.76%）、ST744（5.88%）和ST10（5.88%） ）。此外，在本研究中确定了新的 ST。

结论

我们的结果表明，从波兰家禽中分离出的mcr-1阳性大肠杆菌菌株的发生率很低；然而，所有分离的菌株都对多种抗菌剂具有抗性，并且能够形成低或中等水平的生物膜。