Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
College of Veterinary Medicine, Iowa State University, Ames, Iowa 50011-1134, USA.
Nat Microbiol. 2017 Feb 6;2:16260. doi: 10.1038/nmicrobiol.2016.260.
By 2030, the global population will be 8.5 billion, placing pressure on international poultry production, of which China is a key producer. From April 2017, China will implement the withdrawal of colistin as a growth promoter, removing over 8,000 tonnes per year from the Chinese farming sector. To understand the impact of banning colistin and the epidemiology of multi-drug-resistant (MDR) Escherichia coli (using bla and mcr-1 as marker genes), we sampled poultry, dogs, sewage, wild birds and flies. Here, we show that mcr-1, but not bla, is prevalent in hatcheries, but bla quickly contaminates flocks through dogs, flies and wild birds. We also screened samples directly for resistance genes to understand the true breadth and depth of the environmental and animal resistome. Direct sample testing for bla and mcr-1 in hatcheries, commercial farms, a slaughterhouse and supermarkets revealed considerably higher levels of positive samples than the bla- and mcr-1-positive E. coli, indicating a substantial segment of unseen resistome-a phenomenon we have termed the 'phantom resistome'. Whole-genome sequencing identified common bla-positive E. coli shared among farms, flies, dogs and farmers, providing direct evidence of carbapenem-resistant E. coli transmission and environmental contamination.
到 2030 年，全球人口将达到 85 亿，这给国际家禽生产带来了压力，而中国是主要的生产国之一。自 2017 年 4 月起，中国将实施停止使用黏菌素作为生长促进剂的措施，每年将从中国农业部门减少 8000 多吨的黏菌素使用。为了了解禁止使用黏菌素和多药耐药（MDR）大肠杆菌（使用 bla 和 mcr-1 作为标记基因）的流行病学情况，我们对家禽、狗、污水、野生鸟类和苍蝇进行了采样。在这里，我们发现 mcr-1，但不是 bla，在孵化场中普遍存在，但 bla 通过狗、苍蝇和野生鸟类迅速污染了禽类。我们还直接筛选了耐药基因样本，以了解环境和动物耐药组的真实范围和深度。直接在孵化场、商业农场、屠宰场和超市对 bla 和 mcr-1 进行样本检测，发现阳性样本的比例明显高于 bla 和 mcr-1 阳性的大肠杆菌，这表明存在大量未被发现的耐药组——我们称之为“幻影耐药组”。全基因组测序确定了农场、苍蝇、狗和农民之间共同存在的 bla 阳性大肠杆菌，提供了碳青霉烯类耐药大肠杆菌传播和环境污染的直接证据。
