Anthropogenic activities and pollution are impacting marine environments globally. As a consequence, increasing numbers of human-associated phylotypes of Escherichia coli, an indicator of fecal contamination, have been found in both aquatic environments and marine mammals considered sentinels for marine health. The objective of this study was to determine the presence and diversity of E. coli in pups of three species of free-ranging pinnipeds in Australia. Fecal samples (n = 963) were collected between 2016 and 2019 from Australian sea lion (Neophoca cinerea), Australian fur seal (Arctocephalus pusillus doriferus) and long-nosed fur seal (Arctocephalus forsteri) pups from eight breeding colonies extending along the Southern Australian coast. E. coli were isolated from 842 (87.3%) samples and molecular screening was applied to assign isolates to E. coli phylotypes and sub-types. The human associated E. coli phylotype B2 was the most frequently isolated in all species at seven of the eight colonies, with 73.7% of all E. coli isolates belonging to this phylotype. Phylotype distribution did not differ significantly within or across species, breeding colonies or breeding seasons. Analysis of B2 isolates into sub-types showed a significant difference in sub-type distribution across breeding seasons at two colonies (Seal Rocks and Cape Gantheaume). The predominance of the B2 phylotype could indicate that all colonies are exposed to similar levels of anthropogenic pollution. This widespread occurrence of the human-associated E. coli phylotypes highlights the imperative for ongoing monitoring and surveillance of microbes in both the marine environment and sentinel species.

中文翻译：

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三种澳大利亚鳍足类幼崽中大肠杆菌的多样性和分布

人为活动和污染正在影响全球的海洋环境。因此，在水生环境和被视为海洋健康哨兵的海洋哺乳动物中发现了越来越多的人类相关大肠杆菌系统发育型，这是粪便污染的指标。本研究的目的是确定澳大利亚三种自由放养的鳍足类动物幼崽中大肠杆菌的存在和多样性。2016 年至 2019 年期间，从澳大利亚海狮 (Neophoca cinerea)、澳大利亚海狗 (Arctocephalus pusillus doriferus) 和长鼻海狗 (Arctocephalus forsteri) 幼崽中收集了粪便样本 (n = 963)，这些幼崽来自澳大利亚南部沿线的八个繁殖群海岸。从 842 (87.3%) 个样本中分离出大肠杆菌，并应用分子筛选将分离株分配给大肠杆菌。大肠杆菌系统发育型和亚型。在八个菌落中的七个菌落中，人类相关的大肠杆菌系统发育型 B2 是所有物种中最常分离的，所有大肠杆菌分离株中有 73.7% 属于这种系统发育型。系统型分布在物种内部或物种之间、繁殖群落或繁殖季节之间没有显着差异。B2 分离株的亚型分析表明，两个种群（Seal Rocks 和 Cape Gantheaume）在繁殖季节的亚型分布存在显着差异。B2 系统发育型的优势可能表明所有菌落都暴露于类似水平的人为污染。这种与人类相关的大肠杆菌系统发育型的广泛发生凸显了对海洋环境和哨兵物种中微生物进行持续监测和监测的必要性。