青藏高原部分地区自由放牧与舍饲育肥牦牛食源性致病微生物污染的差异

摘要

Pathogenic microorganisms in meat are one of the most important factors in human food-borne diseases. In the present study, the prevalence of Salmonella, coliform bacteria, Staphylococcus aureus and Listeria monocytogenes in various yak tissues, and the serological identification and antibiotic resistance of Salmonella were investigated. Totally, 277 samples of muscle and visceral tissues from yaks in Northwest Sichuan plateau were collected including 155 samples from free grazing yaks and 122 samples from stall-fed fattening yaks both without diarrhea symptoms. The results showed that no significant difference in the carrier rate of pathogenic microorganisms in various yak tissues was between two feeding regimens (P > 0.05), but the absolute value of detection rate in free grazing yak was higher than that in stall-fed fattening yak. Different Salmonella serotypes were isolated from yak tissue samples from two different feeding systems. The Salmonella serotypes isolated from stall-fed fattening and grazing yak muscle were S. newport and S. enteritidis, respectively. The Salmonella serotypes isolated from fecal samples of grazing yak were S. typhimurium, S. enteritidis and S. saintpaul, while only S. dublin was isolated from fecal samples of stall-fed fattening yaks. The feeding regimens had no effect on the antibiotic resistance of Salmonella isolated from yaks, and the Salmonella isolated from stall-fed and free grazing yaks showed high resistance to lincomycin (83.33% and 81.82%), tetracycline (66.67% and 63.64%), and midecamycin (66.67%and 72.73%). Overall, the microbiological safety of yaks was identical between two feeding regimens, and the antibiotic resistance of Salmonella isolated from the yaks was high.%肉中的致病微生物污染是危害人类健康的重要因素.本研究采集了青藏高原部分地区无腹泻症状的放牧型牦牛样品155份,舍饲育肥型牦牛样品122份,对其粪便及各组织中沙门氏菌、大肠菌群、金黄色葡萄球菌和单增李斯特菌进行分离,并对沙门氏菌进行血清学鉴定和抗生素药敏实验.结果发现,2种饲养方式下,牦牛组织病原微生物携带率统计学上无显著差异(P>0.05),但放牧型牦牛的检出率绝对值都略高于舍饲育肥型牦牛;2种不同饲养方式的牦牛样品中分离出的沙门氏菌血清型差异较大,舍饲育肥型和放牧型牦牛肌肉中检出的血清型分别为纽波特沙门氏杆菌和肠炎沙门氏杆菌,放牧型牦牛粪便中的沙门氏菌为鼠伤寒沙门氏杆菌、肠炎沙门氏杆菌和圣保罗沙门氏菌,而舍饲育肥型牦牛仅有都柏林沙门氏菌;舍饲育肥型和放牧型牦牛源沙门氏菌对抗生素耐药性规律基本一致,对林可霉素(83.33%、81.82%)、四环素(66.67%、63.64%)和麦迪霉素(66.67%、72.73%)具有较高的耐药性.从实验结果可以得出,放牧型牦牛的微生物安全性和舍饲育肥型牦牛一致,沙门氏菌对抗生素的耐药性都较为严重.