西藏林芝地区腹泻藏猪源大肠杆菌mcr-1基因调查分析

本研究旨在调查藏猪腹泻源大肠杆菌mcr-1的流行情况。从舍饲藏猪养殖场53份腹泻样品中分离到102株大肠杆菌。采用Kirby-Bauer纸片扩散法进行药敏试验，利用PCR扩增多粘菌素耐药基因mcr-1,并对mcr-1阳性菌株扩增β-内酰胺酶耐药基因、喹诺酮类耐药基因、氨基糖苷类耐药基因、四环素类耐药基因(tetA和tetB)和磺胺类耐药基因和氯霉素类耐药基因。结果显示，102株大肠杆菌中mcr-1检出率为32.4%。mcr-1阳性菌株对氯霉素、四环素和氨苄青霉素的耐药性较高，分别为88.2%、86.3%和84.3%。mcr-1阳性菌株中β-内酰胺酶耐药基因blaCTX-M的检出率最高，为84.8%;喹诺酮类耐药基因中qnrS检出率最高，为45.5%;氨基糖苷类耐药基因中aac(6)-Ib检出率最高，为48.5%。四环素类耐药基因tetA和tetB检出率分别为39.4%和54.5%;磺胺类耐药基因sul1、sul2和sul3检出率分别为100%、97%和78.8%;氯霉素类耐药基因cmlA和floR检出率分别为72.7%和84.8%。结果说明藏猪腹泻源大肠杆菌mcr-1阳性菌株的多重耐药...

Epidemiological Analysis of Colistin-resistant Gene mcr-1 in Escherichia coli from Diarrheic Weaned Piglets in Nyingchi of Tibet

To investigate the prevalence of colistin-resistant gene mcr-1 of Escherichia coli isolated from diarrheic weaned piglets in Tibet, a total of 53 diarrhea fecal samples were collected and 102 strains E.coli were isolated. Antimicrobial susceptibility testing was carried out using the Kirby-Bauer disk diffusion method. PCR was used to amplify the colistin resistant gene mrc-1 and mcr-1 positive strains were screened for other resistance genes, including beta-lactam resistance genes, quinolone resistance genes, aminoglycoside resistance genes, tetracycline resistance genes, sulphonamide resistance genes and chloramphenicol resistance genes. The results showed that 32.4% of E. coli harboured mcr-1 gene were detected in 102 strains of E. coli .The mcr-1 positive strains showed high resistance rate to chloramphenicol (88.2%), tetracycline (86.3%) and ampicillin (84.3%).The most prevalent beta-lactam resistance gene was blaCTX-M (84.8%). The most prevalent quinolone resistance gene was qnrS (45.5%). The most prevalent aminoglycoside resistance gene was aac(6)- Ib (48.5%). Two tetracycline resistance genes tetA and tetB were carried by 39.4% and 54.5% ,respectively. Three sulphonamide resistance genes were carried by 100%, 97% and 78.8%, respectively. Two chloramphenicol resistance genes were carried by 72.7% and 84.8%,respectively. In conclusion the multi-drug resistance of mcr-1 positive strains of E. coli from diarrheic weaned piglets in Tibet is serious, which may cause widespread and threaten public health safety.