质粒介导的喹诺酮类耐药决定因子在突尼斯动物源大肠杆菌中的流行：特定的血清型获得了 qnr 基因。
Occurrence of plasmid-mediated quinolone resistance determinants among Escherichia coli strains isolated from animals in Tunisia: Specific pathovars acquired qnr genes.
机构信息
Université de Tunis El Manar, Institut de la Recherché Vétérinaire de Tunisie, Tunis 1006, Tunisia; Université de Tunis El Manar, Faculté de Médecine de Tunis, LR99ES09 Laboratoire de Recherche 'Résistance aux Antimicrobiens', Tunis 1007, Tunisia.
Université de Tunis El Manar, Faculté de Médecine de Tunis, LR99ES09 Laboratoire de Recherche 'Résistance aux Antimicrobiens', Tunis 1007, Tunisia.
出版信息
J Glob Antimicrob Resist. 2020 Mar;20:50-55. doi: 10.1016/j.jgar.2019.07.023. Epub 2019 Jul 28.
OBJECTIVES
The aim of this study was to characterise Escherichia coli strains harbouring plasmid-mediated quinolone resistance (PMQR) genes recovered from various samples (n = 116) from healthy and diarrhoeic animals in Tunisia.
METHODS
All nalidixic acid-resistant E. coli isolates were screened for the presence of PMQR genes. Isolates positive for PMQR genes were investigated by PCR for chromosomal mutations in the quinolone resistance-determining regions (QRDRs) of GyrA and ParC, the presence of class 1 and class 2 integrons, genes encoding tetracycline and sulfonamide resistance, genes encoding virulence factors, and phylogenetic group. Genetic relationships was determined by pulsed-field gel electrophoresis (PFGE).
RESULTS
Amongst 51 nalidixic acid-resistant isolates, 9 harboured PMQR genes (5 co-harbouredqnrS1 and qnrB1, 3 harboured qnrS1 and 1 harboured qnrB1). Two types of mutation in the QRDR of GyrA were observed: S83L and D87N (eight isolates) and S83L (one isolate). For the QRDR of ParC, the substitution S80I was observed in four isolates. A class 1 integron was found in six isolates. The tetA or tetB gene was observed in six isolates and both tetA and tetB were co-harboured by two isolates. The sul1, sul2 and sul3 genes were detected in six, four and one isolates, respectively. According to the presence of specific virulence genes, the nine strains were classified as UPEC (5), EAEC (3) and EPEC (1). Three isolates from turkey faeces were clonally related by PFGE.
CONCLUSION
These findings highlight the plausible role of the avian industry as a reservoir of human pathogenic E. coli strains.
目的
本研究旨在对从突尼斯健康和腹泻动物的各种样本（n=116）中分离的携带质粒介导的喹诺酮耐药（PMQR）基因的大肠杆菌菌株进行特征描述。
方法
所有耐萘啶酸的大肠杆菌分离株均进行了 PMQR 基因的筛选。对携带 PMQR 基因的分离株进行了 PCR 检测，以确定喹诺酮耐药决定区（QRDR）中 GyrA 和 ParC 的染色体突变、1 类和 2 类整合子、编码四环素和磺胺类耐药的基因、编码毒力因子的基因和进化群。通过脉冲场凝胶电泳（PFGE）确定遗传关系。
结果
在 51 株耐萘啶酸的分离株中，有 9 株携带 PMQR 基因（5 株同时携带 qnrS1 和 qnrB1，3 株携带 qnrS1，1 株携带 qnrB1）。在 GyrA 的 QRDR 中观察到两种类型的突变：S83L 和 D87N（8 株）和 S83L（1 株）。在 ParC 的 QRDR 中，观察到 S80I 取代了 4 株。在 6 株分离株中发现了 1 类整合子。在 6 株分离株中观察到 tetA 或 tetB 基因，2 株同时携带 tetA 和 tetB 基因。在 6、4 和 1 株分离株中分别检测到 sul1、sul2 和 sul3 基因。根据特定毒力基因的存在，这 9 株菌被分类为 UPEC（5 株）、EAEC（3 株）和 EPEC（1 株）。通过 PFGE，从火鸡粪便中分离出的 3 株分离株具有克隆相关性。
结论
这些发现强调了禽类产业可能是人类致病性大肠杆菌菌株的储存库。
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