Cytotoxicity and Antimicrobial Resistance of Salmonella enterica Subspecies Isolated from Raised Reptiles in Beijing, China

Dingka Song; Xuebai He; Yiming Chi; Zhao Zhang; Jing Shuai; Hui Wang; Qiuming Li; Mengze Du

doi:10.3390/ani13020315

Cytotoxicity and Antimicrobial Resistance of Salmonella enterica Subspecies Isolated from Raised Reptiles in Beijing, China

Animals (Basel). 2023 Jan 16;13(2):315. doi: 10.3390/ani13020315.

Authors

Dingka Song^{1

2}, Xuebai He¹, Yiming Chi¹, Zhao Zhang¹, Jing Shuai¹, Hui Wang², Qiuming Li¹, Mengze Du¹

Affiliations

¹ Animal Science and Technology College, Beijing University of Agriculture, National Demonstration Center for Experimental Animal Education, Beijing 102206, China.
² State Key Laboratory of Oncogenes and Related Genes, Center for Single-Cell Omics, School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.

Abstract

Background: Reptiles are asymptomatic carriers of Salmonella spp. Reptile-associated Salmonella infections have been noticed as a significant contributor to overall human salmonellosis. However, it remains unclear regarding the prevalence of reptile-associated Salmonella in China.

Methods: Fecal and gastrointestinal mucosal samples were taken from 104 snakes, 21 lizards, and 52 chelonians and cultured on selective medium. The positive clones were validated and annotated by biochemical screening and multiplex PCR verification. In addition, the antibiotic resistance of identified Salmonella isolates was detected and followed by cytotoxic activity detection on human colon cells via co-culturation.

Results: The overall prevalence of Salmonella in reptiles was 25.99%, with rates of 30.77%, 47.62%, and 7.69% in snakes, lizards, and chelonians, respectively. Further, all isolates showed variable drug-resistant activity to 18 antibiotics, of which 14 strains (30.43%) were resistant to more than eight kinds of antibiotics. More than half of isolated Salmonella strains were more toxic to host cells than the standard strain, SL1344. Whole genome sequencing (WGS) results showed that all lizard-associated strains belong to 4 serovar types, and 7 of them fall into the highly pathogenic serovars "Carmel" and "Pomona."

Conclusions: Our results highlight the potential threat of zoonotic salmonellosis from captive reptiles in the Beijing area of China.

Keywords: Salmonella spp.; antibiotic resistance; cytotoxicity; reptiles; zoonotic disease.

Grants and funding

This research was funded by the National Natural Science Foundation of China (32200749), the Natural Science Foundation of Shanghai (22ZR1435900), the Science and Technology Innovation “Sparking” Support Program of Beijing University of Agriculture (BUA-HHXD2022007), and the Research and Innovation Ability Improvement Plan for Young Teachers (QJKC2022029). D.S. was also supported by a research grant from the Startup Fund for Young Faculty at SJTU (SFYF at SJTU).