Data from: Evidence of land-sea transfer of the zoonotic pathogen Campylobacter to a wildlife marine sentinel species

Environmental pollution often accompanies the expansion and urbanization of human populations where sewage and wastewaters commonly have an impact on the marine environments. Here, we explored the potential for faecal bacterial pathogens, of anthropic origin, to spread to marine wildlife in coastal areas. The common zoonotic bacterium Campylobacter was isolated from grey seals (Halichoerus grypus), an important sentinel species for environmental pollution, and compared to isolates from wild birds, agricultural sources and clinical samples to characterize possible transmission routes. Campylobacter jejuni was present in half of all grey seal pups sampled (24/50 dead and 46/90 live pups) in the breeding colony on the Isle of May (Scotland), where it was frequently associated with histological evidence of disease. Returning yearling animals (19/19) were negative for C. jejuni suggesting clearance of infection while away from the localized colony infection source. The genomes of 90 isolates from seals were sequenced and characterized using a whole-genome multilocus sequence typing (MLST) approach and compared to 192 published genomes from multiple sources using population genetic approaches and a probabilistic genetic attribution model to infer the source of infection from MLST data. The strong genotype-host association has enabled the application of source attribution models in epidemiological studies of human campylobacteriosis, and here assignment analyses consistently grouped seal isolates with those from human clinical samples. These findings are consistent with either a common infection source or direct transmission of human campylobacter to grey seals, raising concerns about the spread of human pathogens to wildlife marine sentinel species in coastal areas.人口扩张与城市化进程往往伴随环境污染问题，而生活污水及废水通常会对海洋环境产生负面影响。本研究旨在探究人类来源的粪便源性细菌病原体向沿海地区海洋野生动物传播的可能性。研究从灰海豹（Halichoerus grypus，一种重要的环境污染指示物种）中分离得到了常见人畜共患病细菌——弯曲杆菌（Campylobacter），并将该分离株与野生鸟类、农业来源及临床样本中的分离株进行比对，以解析其潜在传播路径。在苏格兰五月岛（Isle of May）的繁殖种群中，近半数被采样的灰海豹幼崽（24/50死亡幼崽、46/90存活幼崽）携带空肠弯曲杆菌（Campylobacter jejuni），且该菌常与组织病理学层面的病变证据相关联。时隔一年返回该繁殖地的一岁龄亚成体海豹（19/19）均呈空肠弯曲杆菌阴性，这表明它们在离开该局部感染源种群后，体内的感染已被清除。研究人员对90株海豹来源的分离株进行了全基因组测序，并采用全基因组多位点序列分型（MLST）技术对其进行特征分析；同时结合群体遗传学方法与概率性遗传溯源模型，将这些基因组与192株已发表的多来源菌株基因组进行比对，以基于MLST数据推断感染源。基因型与宿主间的强关联性使得溯源模型可应用于人类弯曲杆菌病的流行病学研究，本研究的分型分析结果始终将海豹分离株与人类临床样本分离株归为一类。上述研究结果支持两种可能性：一是二者共享同一感染源，二是人类携带的弯曲杆菌可直接传播给灰海豹，这引发了人们对人类病原体向沿海地区海洋野生动物指示物种传播的担忧。