Salmonella Typhimurium with Eight Tandem Copies of bla NDM-1 on a HI2 Plasmid

• Published in: Microorganisms (Basel) 2023-12, Vol.12 (1)
• Main Authors: Song, Huijuan, Zou, Siyu, Huang, Yi, Jian, Cui, Liu, Weiyong, Tian, Lei, Gong, Lu, Chen, Zhongju, Sun, Ziyong, Wang, Yue
• Format: Article
• Language: English
• ISSN: 2076-2607; 2076-2607
• DOI: 10.3390/microorganisms12010020

Carbapenem-resistant has recently aroused increasing attention. In this study, a total of four sequence type 36 subsp. serovar Typhimurium ( Typhimurium) isolates were consecutively isolated from an 11-month-old female patient with a gastrointestinal infection, of which one was sensitive to carbapenems and three were resistant to carbapenems. Via antibiotic susceptibility testing, a carbapenemases screening test, plasmid conjugation experiments, Illumina short-reads, and PacBio HiFi sequencing, we found that all four Typhimurium isolates contained a -positive IncI1 plasmid. One carbapenem-sensitive Typhimurium isolate then obtained an IncHI2 plasmid carrying and an IncP plasmid without any resistance genes during the disease progression. The gene was located on a new 30 kb multiple drug resistance region, which is flanked by IS and TnAs2, respectively. In addition, the ST_F0903R isolate contained eight tandem copies of the IS unit (IS - - - - -IS Δ1), but an increase in MICs to carbapenems was not observed. Our work further provided evidence of the rapid spread and amplification of through plasmid. Prompting the recognition of carbapenem-resistant and the initiation of appropriate infection control measures are essential to avoid the spread of these organisms.