Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan, ROC; Division of Pediatric Infectious Diseases, Chang Gung Children's Hospital, Taoyuan, Taiwan, ROC.
Medical Laboratory Division, Chiayi Branch, Taichung Veterans General Hospital, No.600, Sec. 2, Shixian Rd., Chiayi City, 60090, Taiwan, ROC.
J Microbiol Immunol Infect. 2021 Aug;54(4):649-657. doi: 10.1016/j.jmii.2020.01.008. Epub 2020 Feb 28.
Nontyphoid Salmonella and Shigella can cause gastroenteritis in humans. Ceftriaxone (CRO) has been used to treat their infection, however, development of CRO resistance are often associated with plasmid-mediated bla Here, we investigated the presence of plasmid-mediated ISEcp-1 tnpA-bla-blc-sugE and the role of these genes in regulation of CRO susceptibility in different hosts.
194 strains of Salmonella serovars and Shigella were tested for CRO susceptibility. Non-susceptibility strains were examined for plasmid-mediated ISEcp-1 tnpA-bla-blc-sugE by PCR amplification, Southern blot, and DNA sequencing. The plasmid profiles were determined by HindIII-digested restriction fragment length polymorphism (RFLP). Four recombinant plasmids with different genes from ISEcp-1 tnpA-bla-blc-sugE were constructed and then were transferred into Escherichia coli and different Salmonella serovars to evaluate the CRO susceptibility.
Among 20 CRO-nonsusceptible isolates of Salmonella Choleraesuis (5), S. Typhimurium (4), S. Mons (1), S. Stanley (2) and Shigella sonnei (8) with plasmid-mediated bla 19 isolates carried the ISEcp-1 tnpA-bla-blc-sugE and only one isolate with tnpA-bla. Transformation of these plasmids into E. coli pir116 produced multidrug resistance. Furthermore, PCR-RFLP analysis determined 5 different plasmid profiles and identical RFLP pattern between S. Typhimurium and S. sonnei. Transformation of the recombinant plasmids into E. coli and different Salmonella serovars resulted in phenotypes ranging from susceptible to resistant (especially inducible resistance) to CRO that were dependent on the genes, and host.
The CRO susceptibility associated with the ISEcp-1 tnpA-bla-blc-sugE element is regulated positively by ISEcp-1 tnpA and SugE and negatively regulated by Blc and unknown species-dependent host factor(s).
非伤寒沙门氏菌和志贺氏菌可引起人类肠胃炎。头孢曲松（CRO）已被用于治疗其感染，但 CRO 耐药性的发展通常与质粒介导的 bla 有关。在这里，我们研究了质粒介导的 ISEcp-1 tnpA-bla-blc-sugE 的存在及其在不同宿主中调节 CRO 敏感性的作用。
对 194 株沙门氏菌血清型和志贺氏菌进行 CRO 敏感性测试。非敏感性菌株通过 PCR 扩增、Southern blot 和 DNA 测序检测质粒介导的 ISEcp-1 tnpA-bla-blc-sugE。通过 HindIII 消化限制性片段长度多态性（RFLP）确定质粒图谱。从 ISEcp-1 tnpA-bla-blc-sugE 中构建了 4 个具有不同基因的重组质粒，然后将其转移到大肠杆菌和不同的沙门氏菌血清型中，以评估 CRO 敏感性。
在 20 株 CRO 不敏感的霍乱沙门氏菌（5 株）、鼠伤寒沙门氏菌（4 株）、蒙氏沙门氏菌（1 株）、斯坦利沙门氏菌（2 株）和宋内志贺氏菌（8 株）中，有 19 株携带 bla 基因。19 株携带 ISEcp-1 tnpA-bla-blc-sugE 的菌株中，只有 1 株携带 tnpA-bla。这些质粒转化到大肠杆菌 pir116 中产生了多药耐药性。此外，PCR-RFLP 分析确定了 5 种不同的质粒图谱，鼠伤寒沙门氏菌和宋内志贺氏菌之间的 RFLP 模式相同。将重组质粒转化到大肠杆菌和不同的沙门氏菌血清型中，导致 CRO 表型从敏感到耐药（特别是诱导耐药）不等，这取决于基因和宿主。
与 ISEcp-1 tnpA-bla-blc-sugE 元件相关的 CRO 敏感性受 ISEcp-1 tnpA 和 SugE 的正调控，受 Blc 和未知种属依赖性宿主因子的负调控。
