MOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology and State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, China.
MOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology and State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, China; National Health Commission (NHC) Key Laboratory of Tropical Disease Control, School of Tropical Medicine, Hainan Medical University, China.
Int J Food Microbiol. 2024 Jun 2;417:110708. doi: 10.1016/j.ijfoodmicro.2024.110708. Epub 2024 Apr 19.
Salmonella Thompson is a prevalent foodborne pathogen and a major threat to food safety and public health. This study aims to reveal the dissemination mechanism of S. Thompson with co-resistance to ceftriaxone and ciprofloxacin. In this study, 181 S. Thompson isolates were obtained from a retrospective screening on 2118 serotyped Salmonella isolates from foods and patients, which were disseminated in 12 of 16 districts in Shanghai, China. A total of 10 (5.5 %) S. Thompson isolates exhibited resistance to ceftriaxone (MIC ranging from 8 to 32 μg/mL) and ciprofloxacin (MIC ranging from 2 to 8 μg/mL). The AmpC β-lactamase gene bla and plasmid-mediated quinolone resistance (PMQR) genes of qnrS and qepA were identified in the 9 isolates. Conjugation results showed that the co-transfer of bla, qnrS, and qepA occurred on the IncC plasmids with sizes of ∼150 (n = 8) or ∼138 (n = 1) kbp. Three typical modules of ISEcp1-bla-blc-sugE, IS26-IS15DIV-qnrS-ISKpn19, and ISCR3-qepA-intl1 were identified in an ST3 IncC plasmid pSH11G0791. Phylogenetic analysis indicated that IncC plasmids evolved into Lineages 1, 2, and 3. IncC plasmids from China including pSH11G0791 in this study fell into Lineage 1 with those from the USA, suggesting their close genotype relationship. In conclusion, to our knowledge, it is the first report of the co-existence of bla, qnrS, and qepA in IncC plasmids, and the conjugational transfer contributed to their dissemination in S. Thompson. These findings underline further challenges for the prevention and treatment of Enterobacteriaceae infections posed by IncC plasmids bearing bla, qnrS, and qepA.
沙门氏菌汤普森是一种普遍存在的食源性病原体，对食品安全和公共健康构成重大威胁。本研究旨在揭示对头孢曲松和环丙沙星具有共耐药性的沙门氏菌汤普森的传播机制。在这项研究中，从中国上海 16 个区的 2118 份血清型沙门氏菌分离物的回顾性筛查中获得了 181 株沙门氏菌汤普森分离株。共有 10（5.5%）株沙门氏菌汤普森分离株对头孢曲松（MIC 范围为 8 至 32μg/mL）和环丙沙星（MIC 范围为 2 至 8μg/mL）表现出耐药性。在 9 株菌中鉴定出 AmpC β-内酰胺酶基因 bla 和质粒介导的喹诺酮耐药（PMQR）基因 qnrS 和 qepA。接合结果表明，bla、qnrS 和 qepA 的共转移发生在大小约为 150（n=8）或 138（n=1）kbp 的 IncC 质粒上。在 ST3 IncC 质粒 pSH11G0791 中鉴定出三个典型的 ISEcp1-bla-blc-sugE、IS26-IS15DIV-qnrS-ISKpn19 和 ISCR3-qepA-intl1 模块。系统发育分析表明，IncC 质粒进化为谱系 1、2 和 3。包括本研究中的 pSH11G0791 在内的来自中国的 IncC 质粒与来自美国的质粒一起属于谱系 1，表明它们具有密切的基因型关系。总之，据我们所知，这是首次报道 IncC 质粒中同时存在 bla、qnrS 和 qepA，并且接合转移有助于它们在沙门氏菌汤普森中的传播。这些发现突显了携带 bla、qnrS 和 qepA 的 IncC 质粒对肠杆菌科感染的预防和治疗带来的进一步挑战。
