Xie Mengyuan, Chen Yexin, Shang Hewei, He Xiuling, Xu Xiaojing
College of Veterinary Medicine, Inner Mongolia Agricultural University, Hohhot, China.
Key Laboratory of Clinical Diagnosis and Treatment Technology in Animal Disease, Ministry of Agriculture and Rural Affairs, Hohhot, China.
BMC Vet Res. 2025 Jul 8;21(1):452. doi: 10.1186/s12917-025-04901-x.
Salmonella poses a significant health threat to both humans and animals owing to the emergence of antimicrobial-resistant strains. There are no studies on the incidence patterns of salmonellosis and multidrug-resistant Salmonella strains in Inner Mongolia, China's milk and beef-producing hotspot. Farms in Inner Mongolia, China, were randomly selected, and rectal swabs (600) and milk samples (757) were collected for isolation and identification of Salmonella, and antimicrobial resistance was assessed according to CLSI and NARMS guidelines. Twenty-one resistance genes from seven classes of antibiotics were selected for detection using polymerase chain reaction (PCR), and Salmonella-NMGS9 was selected for whole genome sequencing and drug resistance gene prediction analysis.
Salmonella was found in 24 (85.71%) of the 28 large-scale cattle farms in Inner Mongolia, China, resulting in 176 Salmonella strains from 1357 samples (with a prevalence of 3.88%). Of the 158 strains tested for their susceptibility to 19 antibiotics, multidrug-resistant (MDR) strains accounted for 90.51% (143/158), and 6 strains were only resistant to sulfisoxazole. Furthermore, 40% and 30% of the strains had sul3 and sul1 genes; all strains were sensitive to polymixin B, and no strains had the mcr-1 gene. Among the 8 S. enterica strains (5.59%), 14 genes were identified, with the β-lactam gene bla expressed in all MDR isolates. Only the floR and tetB genes were consistent with the PCR results for the predicted drug resistance genes in Salmonella-NMGS9 strains.
This study is the first to determine the prevalence, antimicrobial resistance, and genetic characteristics, of Salmonella spp. isolated from large-scale cattle farms in Inner Mongolia, China. Monitoring the prevalence, resistance gene expression, and distribution of Salmonella on large-scale cattle farms in Inner Mongolia is vital for understanding the extent and trends in foodborne pathogen resistance in China.
由于抗菌耐药菌株的出现，沙门氏菌对人类和动物都构成了重大的健康威胁。在中国内蒙古这个牛奶和牛肉生产的热点地区，尚无关于沙门氏菌病和多重耐药沙门氏菌菌株发病率模式的研究。随机选取了中国内蒙古的养殖场，采集直肠拭子（600份）和牛奶样本（757份）用于沙门氏菌的分离和鉴定，并根据CLSI和NARMS指南评估抗菌药物耐药性。选择七类抗生素中的21个耐药基因，采用聚合酶链反应（PCR）进行检测，并选择沙门氏菌-NMGS9进行全基因组测序和耐药基因预测分析。
在中国内蒙古的28个大型养牛场中，有24个（85.71%）检测到沙门氏菌，从1357份样本中分离出176株沙门氏菌菌株（患病率为3.88%）。在对158株菌株进行19种抗生素敏感性测试中，多重耐药（MDR）菌株占90.51%（143/158），6株仅对磺胺异恶唑耐药。此外，40%和30%的菌株分别有sul3和sul1基因；所有菌株对多粘菌素B敏感，无菌株携带mcr-1基因。在8株肠炎沙门氏菌菌株（5.59%）中，鉴定出14个基因，所有MDR分离株均表达β-内酰胺基因bla。只有floR和tetB基因与沙门氏菌-NMGS9菌株预测的耐药基因PCR结果一致。
本研究首次确定了从中国内蒙古大型养牛场分离出的沙门氏菌属的患病率、抗菌药物耐药性和遗传特征。监测内蒙古大型养牛场沙门氏菌的患病率、耐药基因表达和分布，对于了解中国食源性病原体耐药性的程度和趋势至关重要。
