Aquatic recreation in urban estuaries worldwide is often restricted by fecal pollution. Variability in the occurrence of fecal pathogens and their differential virulence potentials within these estuaries may result in variable public health risks. To address this hypothesis, Campylobacter were isolated from the Yarra River estuary, Australia and then characterized via HeLa cell cytotoxicity and attachment to and the invasion of Caco-2 monolayers. Overall, 54% (n=216) of estuarine samples (water and sediment combined) yielded biochemically confirmed culturable Campylobacter; higher detection was recorded in water (92%, n=90) than in the bank and bed sediments combined (27%, n=126). The seasonality of occurrence was not significant. HeLa cell cytotoxicity revealed that estuarine Campylobacter had low cytotoxin titers; the 95% confidence interval (CI) ranged between 61 and 85, which was markedly lower than the mean value (~386) for the C. jejuni 11168 reference pathogenic strain. The Caco-2 attachment of estuarine Campylobacter isolates (n=189) revealed that the 95%CI for the attachment efficiency of the test strains ranged between 0.09 and 0.1%, with only 3.7% having a higher efficiency than the 5th percentile value for C. jejuni 11168. None of the estuarine strains exhibited Caco-2 invasion capabilities. In contrast to the common assumption during quantitative microbial/risk assessments (QMRAs) that all environmental strains are pathogenic, the present results revealed that Campylobacter within the Yarra River estuary had very low virulence potential. Since this is the first study to use human epithelial cell lines to characterize estuary-borne pathogens, these results generate valuable insights for a better understanding of the public health risks in urban estuaries that will underpin more robust QMRAs.

中文翻译：

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城市河口中的弯曲杆菌：从发生、HeLa 细胞毒性和 Caco-2 附着暨入侵中获得的公共卫生见解

世界各地城市河口的水上娱乐活动往往受到粪便污染的限制。这些河口内粪便病原体发生的变异性及其不同的毒力潜力可能导致不同的公共卫生风险。为了解决这一假设，从澳大利亚亚拉河口分离出弯曲杆菌，然后通过 HeLa 细胞的细胞毒性和对 Caco-2 单层的附着和入侵进行表征。总体而言，54% (n=216) 的河口样品（水和沉积物结合）产生了经生化证实的可培养弯曲杆菌；在水中（92%，n=90）比在河岸和河床沉积物的总和（27%，n=126）中记录到更高的检测量。发生的季节性不显着。HeLa 细胞毒性显示河口弯曲杆菌具有低细胞毒素滴度；95% 置信区间 (CI) 介于 61 和 85 之间，明显低于空肠弯曲杆菌 11168 参考致病菌株的平均值 (~386)。河口弯曲杆菌分离株（n=189）的 Caco-2 附着显示测试菌株附着效率的 95%CI 介于 0.09 和 0.1% 之间，只有 3.7% 的效率高于 C 的第 5 个百分位值. jejuni 11168. 没有一个河口菌株表现出 Caco-2 入侵能力。与定量微生物/风险评估 (QMRA) 中所有环境菌株都具有致病性的普遍假设相反，目前的结果显示，亚拉河河口内的弯曲杆菌具有非常低的毒力潜力。由于这是第一项使用人类上皮细胞系来表征河口传播病原体的研究，