Screening and identification of heteroresistant Streptococcus isolates from dairy cows to gentamicin and investigation of their resistance mechanism
10.16303/j.cnki.1005-4545.2025.10.11
- VernacularTitle:奶牛源链球菌对庆大霉素异质性耐药菌株的筛选鉴定及其耐药机制探究
- Author:
Jiaojiao GAO
1
;
Xiaolan HE
;
Nan ZHENG
;
Xiaowei XU
;
Wei SHAO
;
Yankun ZHAO
Author Information
1. 新疆农业科学院农业质量标准与检测技术研究所农业农村部农产品质量安全风险评估实验室(乌鲁木齐)/新疆农产品质量安全实验室,新疆乌鲁木齐 830091;新疆农业大学动物科学学院新疆肉乳用草食动物营养实验室,新疆乌鲁木齐 830052
- Publication Type:Journal Article
- Keywords:
Streptococcus;
gentamicin;
PAP;
heteroresistance;
whole-genome sequencing
- From:
Chinese Journal of Veterinary Science
2025;45(10):2170-2178
- CountryChina
- Language:Chinese
-
Abstract:
This study investigated the prevalence and potential mechanisms of gentamicin heterore-sistance in Streptococcus isolates from dairy cows.In this study,A total of 39 Streptococcus isola-ted from raw milk were collected,and the minimum inhibitory concentration(MIC)of gentamicin and other drugs on the isolates was determined by micro broth dilution method,and the K-B paper diffusion method,colony analysis profile(PAP),and resistance stability test were used to investigate the heteroresistance characteristics of Streptococcus,and the mechanism of heteroresis-tance was analyzed based on whole genome sequencing and resequencing.Seven suspected heterore-sistance strains were identified by K-B paper diffusion method,accounting for 17.95％(7/39)of the total number of suspected strains.PAP confirmed that the MIC to MNIC ratio of L147,L108 and L174 was greater than 8,and the frequency of resistant subgroups ranged from 1.38×10-5 to 8.18 × 10-5,which was greater than 1 × 10-7,confirming that they were heteroresistance strains.Resistance stability tests revealed that the resistant subpopulations of all three strains were not stably inherited.Whole-genome sequencing revealed mutations in the ribosomal target genes of aminoglycoside antibiotics,rsmA,rsmB and rsmE,compared with the reference genome,which may lead to heteroresistance to gentamicin in Streptococcus.The occurrence of heteroresistance of Streptococcus to gentamicin is high in dairy sources,so more attention should be paid to the occur-rence of heteroresistance when using gentamicin for clinical treatment.
