Clinical Characteristics, Antimicrobial Resistance, Virulence Genes and Multi-Locus Sequence Typing of Non-Typhoidal Serovar Typhimurium and Enteritidis Strains Isolated from Patients in Chiang Mai, Thailand.

Non-typhoidal (NTS) caused by ingesting contaminated food or drink remains a major bacterial foodborne disease. Clinical outcomes of NTS range from self-limited gastroenteritis to life-threatening invasive NTS (iNTS). In this study, we isolated spp. from the stool and blood of patients hospitalized at Maharaj Nakorn Chiang Mai Hospital, Chiang Mai, Thailand, between 2016-2021 (a total of 395 cases). Then, serovar Typhimurium and Enteritidis were identified and further characterized by multiplex PCR, and multi-locus sequence typing. Our data show that multidrug resistance (MDR) sequence type 34 (ST34) and ST11 are the predominant sequence types for serovars Typhimurium and Enteritidis, respectively. Most ST34 lacks , and most ST11 harbor , , and genes. NTS can be found in a wide range of ages, and anemia could be a significant factor for infection (86.3%). Both (6.7%) and (25.0%) can cause iNTS in immunocompromised patients. conferred MDR phenotype higher than with multiple antibiotic resistance indexes of 0.22 and 0.04, respectively. Here, we characterized the important , , and human clinical factors of NTS within the region.