Drug resistance and molecular characterization of mcr-1 positive Salmonella typhimurium in Guangzhou, 2013-2020
- Author:
LIN Yongkang
;
WANG Fengwei
;
ZHOU Yong
- Publication Type:Journal Article
- Keywords:
Salmonella typhimurium;
mcr-1;
drug resistance;
PFGE typing;
phylogenetic analysis
- From:
China Tropical Medicine
2024;24(11):1335-
- CountryChina
- Language:Chinese
-
Abstract:
Objective To analyze the basic epidemiological characteristics, drug resistance profiles, molecular characterization features, and phylogenetic relationships of mcr-1 (polymyxin resistance gene, mediated colistin resistance)-positive Salmonella typhimurium collected by Guangzhou Center for Disease Control and Prevention (GZCDC) from 2013 to 2020. Methods Strain identification was performed using a VITEK 2 Compact fully automated microbial biochemical identifier. The mcr-1-positive strains were screened using PCR and agarose gel electrophoresis. The mcr-1-positive strains were subjected to drug sensitivity tests and molecular typing experiments by micro broth dilution and pulse-field gel electrophoresis (PFGE). Whole genome sequencing and phylogenetic analysis were performed on the mcr-1-positive strains. Results From 2013 to 2020, 64 mcr-1-positive strains were screened out of 1 783 Salmonella typhimurium strains, and the mcr-1 positivity rate ranged from 0.37% to 6.84%. The drug sensitivity results showed that all 64 mcr-1 positive strains were resistant to polymyxin and exhibited resistance to ≥3 classes of antibiotics, with 90.63% (58/64) of strains resistant to ≥7 classes. The PFGE results indicated that the 64 positive strains could be grouped into 5 clusters with approximately 70% homology. The phylogenetic tree further suggested the diversity and complexity of transmission pathways of mcr-1-positive Salmonella typhimurium from different sources. Conclusions There has been a high detection rate of mcr-1-positive Salmonella typhimurium in Guangzhou City in recent years, along with a diverse drug resistance spectrum and high genetic diversity among different strains. Continued monitoring and tracing of drug resistance should be strengthened.
- Full text:20251112100519029617.Drug resistance and molecular characterization of mcr-1 positive Salmonella typhimurium in Guangzhou, 2013-2020.pdf
