Microevolution of Salmonella 4,[5],12:i:- derived from Salmonella enterica serovar Typhimurium through complicated transpositions

• Published in: Cell reports (Cambridge) 2023-10, Vol.42 (10), p.113227-113227, Article 113227
• Main Authors: Wang, Zhenyu, Gu, Dan, Hong, Yaming, Hu, Yachen, Gu, Jiaojie, Tang, Yuanyue, Zhou, Xiaohui, Zhang, Yunzeng, Jiao, Xinan, Li, Qiuchun
• Format: Article
• Language: English
• Subjects: CP: Microbiology; IS1R; IS26; resistance regions (RRs); Salmonella enterica serovar Typhimurium (S. Typhimurium); Salmonella enterica subsp. enterica serovar 4,,12:i:- (Salmonella 4,,12:i:-)
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2023.113227

Salmonella enterica subsp. enterica serovar 4,[5],12:i:- (Salmonella 4,[5],12:i:-), derived from S. Typhimurium, has become the dominant serotype causing human salmonellosis. In this study, we define the genetic mechanism of the generation of Salmonella 4,[5],12:i:- from S. Typhimurium through complicated transpositions and demonstrate that Salmonella 4,[5],12:i:- displays more efficient colonization and survival abilities in mice than its parent S. Typhimurium strain. We identified intermediate strains carrying both resistance regions (RRs) and the fljAB operon for the generation of Salmonella 4,[5],12:i:-. The insertion of RR3 into the chromosomal hin-iroB site of S. Typhimurium produced RR3-S. Typhimurium as a primary intermediate. Salmonella 4,[5],12:i:- was then produced by replacing the fljAB operon and/or its flanking sequences through intramolecular transpositions mediated by IS26 and/or IS1R elements in RR3-S. Typhimurium, which was further confirmed both in vitro and in vivo. Overall, we demonstrate the molecular mechanism underlying the origin, generation, and advantage of RRs-Salmonella 4,[5],12:i:- from S. Typhimurium. [Display omitted] •Eight resistance regions (RRs) are identified in Salmonella 4,[5],12:i:- isolates•S. Typhimurium with RR3 inserted into hin-iroB site is a primary intermediate•IS26/IS1R-mediated transposition of RR3-S. Typhimurium created Salmonella 4,[5],12:i:-•RR3-Salmonella 4,[5],12:i:- excels in mouse infection over RR3-S. Typhimurium Salmonella 4,[5],12:i:-, a monophasic variant of S. Typhimurium, has become the predominant serotype causing human salmonellosis. Wang et al. uncover the genetic mechanism of the generation of Salmonella 4,[5],12:i:- from S. Typhimurium. They find that Salmonella 4,[5],12:i:- with various RRs was produced and evolved by IS26/IS1R-mediated complicated transpositions in RR3-S. Typhimurium.