在发达国家,空肠弯杆菌比其他任何一种细菌性病原体引起更多的肠胃炎,甚至比包括大肠杆菌、沙门氏菌、梭菌和李斯特氏菌合起来的还要多。野生及家养动物如同细菌的天然储蓄库,这些细菌在水与土壤中都能生存。但是有关来源的更有价值的信息并不确切,近期的工作显示家畜可能是人类疾病的主要源头。这项研究发表在9 月26 日PLoS Genetics 上。
由芝加哥大学Daniel Wilson 带领的研究团队进行了一项试验,收集了来自1,231 名病人的细菌并对其进行DNA 测序,然后与野生、家养动物和环境中的空肠弯杆菌DNA 序列进行对比。最后利用进化模型追溯人类空肠弯杆菌的来源于七个源头。
57%的病例中,人类空肠弯细菌可以追溯到鸡类空肠弯细菌,35%追溯到牛空肠弯细菌,仅3%与野生动物及环境空肠弯细菌相关。Wilson 认为,家畜是人类疾病的主要来源,但野生动物与环境不是,这就有力地支持了食用被感染的肉类及家禽是主要的传播路线。为证明结果的普遍性,深入的研究正在美国、英国及新西兰进一步展开,通过这项研究可以帮助控制食物源的细菌类疾病。
推荐原始出处:
PLoS Genet 4(9): e1000203. doi:10.1371/journal.pgen.1000203
Tracing the Source of Campylobacteriosis
Daniel J. Wilson, Edith Gabriel, Andrew J. H. Leatherbarrow, John Cheesbrough, Steven Gee, Eric Bolton, Andrew Fox, Paul Fearnhead, C. Anthony Hart, Peter J. Diggle
1 Department of Maths and Statistics, Lancaster University, Lancaster, United Kingdom, 2 Department of Medicine, Lancaster University, Lancaster, United Kingdom, 3 Faculty of Veterinary Science, University of Liverpool, Leahurst, Neston, United Kingdom, 4 Preston Microbiology Services, Royal Preston Hospital, Lancashire Teaching Hospitals NHS Foundation Trust, Preston, United Kingdom, 5 Manchester Medical Microbiology Partnership, Manchester Royal Infirmary, Manchester, United Kingdom, 6 Division of Medical Microbiology, School of Infection and Host Defence, University of Liverpool, Liverpool, United Kingdom
Abstract
Campylobacter jejuni is the leading cause of bacterial gastro-enteritis in the developed world. It is thought to infect 2–3 million people a year in the US alone, at a cost to the economy in excess of US $4 billion. C. jejuni is a widespread zoonotic pathogen that is carried by animals farmed for meat and poultry. A connection with contaminated food is recognized, but C. jejuni is also commonly found in wild animals and water sources. Phylogenetic studies have suggested that genotypes pathogenic to humans bear greatest resemblance to non-livestock isolates. Moreover, seasonal variation in campylobacteriosis bears the hallmarks of water-borne disease, and certain outbreaks have been attributed to contamination of drinking water. As a result, the relative importance of these reservoirs to human disease is controversial. We use multilocus sequence typing to genotype 1,231 cases of C. jejuni isolated from patients in Lancashire, England. By modeling the DNA sequence evolution and zoonotic transmission of C. jejuni between host species and the environment, we assign human cases probabilistically to source populations. Our novel population genetics approach reveals that the vast majority (97%) of sporadic disease can be attributed to animals farmed for meat and poultry. Chicken and cattle are the principal sources of C. jejuni pathogenic to humans, whereas wild animal and environmental sources are responsible for just 3% of disease. Our results imply that the primary transmission route is through the food chain, and suggest that incidence could be dramatically reduced by enhanced on-farm biosecurity or preventing food-borne transmission.