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ORIGINAL RESEARCH article
Front. Microbiol.
Sec. Antimicrobials, Resistance and Chemotherapy
Volume 16 - 2025 |
doi: 10.3389/fmicb.2025.1498995
Genome analysis of colistin-resistant Salmonella isolates from human source in Guizhou of Southwestern China, 2019-2023
Provisionally accepted- 1 Guizhou Medical University, Guiyang, China
- 2 Laboratory of Bacterial Infectious Disease of Experimental Center, Guizhou Provincial Center for Disease Control and Prevention, Guiyang, Guizhou Province, China
Background: Colistin is commonly employed as a last-resort antibiotic for multidrug resistance (MDR) bacterial infections. The emergence of colistin-resistant (CL-R) Salmonella has become a significant public health concern. However, the prevalence of CL-R Salmonella in Guizhou province remains unknown. Therefore, it is necessary to monitor CL-R Salmonella in Guizhou and systematically elucidate their characteristics related resistance, virulence, and molecular epidemiology to develop effective public health strategies against resistant pathogens. Methods: The CL-R Salmonella isolates were identified from 933 Salmonella isolates by antimicrobial resistance testing. To further evaluate the molecular epidemiology, the CL-R Salmonella isolates underwent whole-genome sequencing (WGS) analysis with bioinformatic analysis. Results: A total of 43 CL-R isolates (4.6%) were identified from 933 Salmonella isolates, with 39 isolates being MDR (resistance to three or more classes of antimicrobials) WGS analysis revealed 34 antibiotic resistance genes (ARGs) and point mutations in gyrA gene (D87Y and D87G) were identified in 43 CL-R isolates. Only one isolate carried mcr-1.1 gene, a known colistin resistance. All CL-R isolates were found to carry multidrug efflux pumps. Furthermore, the most common resistance gene was aac(6’)-ly (40/43), followed by blaTEM-1 (39/43). The majority of CL-R isolates contained the virulence factor spvB and a notable diversity in other virulence factors with varied functions. Core genome multilocus sequence typing (cgMLST) revealed that 43 CL-R Salmonella isolates were divided into 19 cgSTs, with cgST179151 (10/43) being the most prevalent. Additionally, the CL-R Salmonella isolates exhibited genetic similarities with human Salmonella isolates from Poland, Canada, and Zhejiang province. Among the 42 CL-R isolates lacking markers for CL-R, twelve single nucleotide variation (SNVs) were observed in 24 isolates by genome-wide association study (GWAS) analysis, which were possibly associated with colistin resistance. Conclusion: This study revealed the majority of CL-R Salmonella isolates in Guizhou province exhibited MDR, with complex resistance mechanisms, representing a significant public health challenge. The genetic similarities between isolates from Guizhou and other regions suggested the possibility of international transmission or shared reservoirs of resistance. These results highlighted the urgent need for enhanced surveillance and effective public health strategies to address the risks posed by these pathogens in Guizhou.
Keywords: whole-genome sequence, Salmonella, Colistin-resistant, mcr-1.1, multidrug resistance
Received: 20 Sep 2024; Accepted: 08 Jan 2025.
Copyright: © 2025 Wu, Wen, You, Wei, Wang, Zhu and Li. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Xiaoyu Wei, Guizhou Medical University, Guiyang, China
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