Animal and Plant Health Agency (Weybridge), New Haw, Addlestone, Surrey, UK.
Animal and Plant Health Agency (Bury St Edmunds), Bury St Edmunds, Suffolk, UK.
J Appl Microbiol. 2018 Aug;125(2):596-608. doi: 10.1111/jam.13907. Epub 2018 May 23.
In 2015, colistin-resistant Escherichia coli and Salmonella with the mcr-1 gene were isolated from a pig farm in Great Britain. Pigs were subsequently monitored over a ~20-month period for the occurrence of mcr-1-mediated colistin resistance and the risk of mcr-1 E. coli entering the food chain was assessed.
Pig faeces and slurry were cultured for colistin-resistant E. coli and Salmonella, tested for the mcr-1 gene by PCR and selected isolates were further analysed. Seventy-eight per cent of faecal samples (n = 275) from pigs yielded mcr-1 E. coli after selective culture, but in positive samples only 0·2-1·3% of the total E. coli carried mcr-1. Twenty months after the initial sampling, faecal samples (n = 59) were negative for E. coli carrying mcr-1.
The risk to public health from porcine E. coli carrying mcr-1 was assessed as very low. Twenty months after cessation of colistin use, E. coli carrying mcr-1 was not detected in pig faeces on a farm where it was previously present.
The results suggest that cessation of colistin use may help over time to reduce or possibly eliminate mcr-1 E. coli on pig farms where it occurs.
2015 年，从英国的一个养猪场分离出了携带 mcr-1 基因的耐药性大肠杆菌和沙门氏菌。随后，对这些猪进行了大约 20 个月的监测，以观察 mcr-1 介导的多黏菌素耐药性的发生情况，并评估 mcr-1 大肠杆菌进入食物链的风险。
对猪的粪便和粪浆进行了选择性培养以分离出耐药性大肠杆菌和沙门氏菌，并通过 PCR 检测 mcr-1 基因，对选定的分离株进行进一步分析。经过选择性培养，78%（n=275）的猪粪便样本中分离出了 mcr-1 大肠杆菌，但在阳性样本中，只有 0.2-1.3%的大肠杆菌携带 mcr-1。初次采样 20 个月后，mcr-1 大肠杆菌不再存在于粪便样本中（n=59）。
从携带 mcr-1 的猪源大肠杆菌对公众健康造成的风险评估为低风险。在停止使用黏菌素 20 个月后，在曾经存在 mcr-1 大肠杆菌的养猪场中，粪便中未检测到携带 mcr-1 的大肠杆菌。
研究结果表明，随着时间的推移，停止使用黏菌素可能有助于减少或可能消除养猪场中存在的 mcr-1 大肠杆菌。
