Water and Food Control Lab, National Center of Salmonella, Shigella, Vibrio-Enteropathogens - Institut Pasteur de Tunis (IPT) Tunis-Belvédère, Tunis, Tunisia.
Department of Biology, College of Sciences, University of Hafar Al-Batin (UHB), City Hafr Al Batin, Saudi Arabia.
J Appl Microbiol. 2021 Mar;130(3):807-818. doi: 10.1111/jam.14822. Epub 2020 Sep 11.
Characterization of quinolone-resistant Salmonella Kentucky and Typhimurium isolates in Tunisia from various sources, detection of some plasmid-mediated quinolone resistance genes and the genetic relatedness.
A total of 1404 isolates of S. Kentucky (n = 1059)/S. Typhimurium (n = 345) from various sources from all over Tunisia were tested for quinolone resistance by disk diffusion method. Minimum inhibitory concentrations of nalidixic acid, ciprofloxacin and ofloxacin were determined. Quinolone-resistant isolates were screened for plasmid-mediated quinolone-resistance genes (qnrA,qnrB,qnrS, aac(6')-Ib-cr and qepA) by polymerase chain reaction (PCR). Mutations in the quinolone-resistance-determining regions of the gyrA and parC genes were detected by PCR and DNA sequencing. Pulsed-field gel electrophoresis and multilocus sequence typing were accomplished for isolates harbouring plasmid-mediated quinolone-resistance genes.
According to our selection criteria (NAL = resistance phenotype; CIP = resistant with diameter 0, or intermediate), only 63 S. Kentucky/41 S. Typhimurium isolates were investigated: 49% (5/104) were multidrug resistant. Two S. Typhimurium isolates harboured qnrB19 with different PFGE profiles. A mutation was detected in the gyrA gene for each of these two isolates. MLST revealed the presence of ST313 and ST34, an endemic sequence type.
Our study highlights the presence of quinolone multidrug-resistant Salmonella in humans and animals in Tunisia. This is the first report of S. Typhimurium ST34 in Africa and qnrB19 in Tunisia.
This is the first report that describes not only the current epidemiological situation of the quinolone resistance in S. Kentucky and Typhimurium isolated from various sources and regions in Tunisia, but also, the genetic resistance determinants associated with phenotypic antibiotic resistance and the molecular mechanisms of their quinolone-resistance. Also, we provide the first report of S. Typhimurium ST34 in Africa, and the first report of qnrB19 in Salmonella in Tunisia.
对来自突尼斯不同来源的耐喹诺酮类药物的肠炎沙门氏菌和鼠伤寒沙门氏菌分离株进行特征描述，检测一些质粒介导的喹诺酮类耐药基因和遗传相关性。
采用纸片扩散法对来自突尼斯各地不同来源的 1404 株肠炎沙门氏菌（n=1059）/鼠伤寒沙门氏菌（n=345）进行了喹诺酮类药物耐药性检测。测定了萘啶酸、环丙沙星和氧氟沙星的最小抑菌浓度。通过聚合酶链反应（PCR）筛选耐喹诺酮类药物的质粒介导的耐药基因（qnrA、qnrB、qnrS、aac（6′）-Ib-cr 和 qepA）。通过 PCR 和 DNA 测序检测喹诺酮类耐药决定区的基因突变。对携带质粒介导的喹诺酮类耐药基因的分离株进行脉冲场凝胶电泳和多位点序列分型。
根据我们的选择标准（NAL=耐药表型；CIP=耐药，直径 0 或中介），仅对 63 株肠炎沙门氏菌/41 株鼠伤寒沙门氏菌进行了研究：49%（5/104）为多药耐药。2 株鼠伤寒沙门氏菌携带不同脉冲场凝胶电泳图谱的 qnrB19。这两种分离株的 gyrA 基因都检测到一个突变。多位点序列分型显示存在 ST313 和 ST34，这是一种地方性序列类型。
本研究突显出耐喹诺酮类药物的沙门氏菌在突尼斯人类和动物中的存在。这是首次在非洲报道鼠伤寒沙门氏菌 ST34 和突尼斯 qnrB19。
这是首次描述不仅来自突尼斯不同来源和地区的肠炎沙门氏菌和鼠伤寒沙门氏菌对喹诺酮类药物的耐药性的当前流行病学情况，还描述了与表型抗生素耐药性相关的遗传耐药决定因素以及它们喹诺酮类耐药的分子机制。此外，我们首次报道了非洲的鼠伤寒沙门氏菌 ST34，以及突尼斯的沙门氏菌 qnrB19。
