Epidemiology of blaCTX-M-Positive Salmonella Typhimurium From Diarrhoeal Outpatients in Guangdong, China, 2010–2017

Salmonella enterica can lead to intestinal diarrhea, and the emergence and spread of cephalosporin-resistant Salmonella have brought great challenges to clinical treatment. Therefore, this study investigated the prevalence and transmission of blaCTX-M genes among S. Typhimurium from diarrhoeal outpatients in Guangdong, China, from 2010 to 2017. A total of 221 blaCTX-M-positive isolates were recovered from 1,263 S. Typhimurium isolates from the facal samples of diarrhoea patients in 45 general hospitals from 11 cities. The most popular CTX-M gene was blaCTX-M-55 (39.6%, 72/182) in the CTX-M-1 group, followed by blaCTX-M-14 (22.5%, 41/182) and blaCTX-M-65 (19.2%, 35/182) in the CTX-M-9 group. The isolates that carried blaCTX-M-9G had significantly higher resistance rates to multiple antibacterials compared with blaCTX-M-1G (p 50%, and it first reported the emergence of blaTEM-141 in S. Typhimurium. This study underscores the importance of surveillance for blaCTX-M-positive microbes in diarrhea patients.