Diversity and Distribution of Escherichia coli in Three Species of Free-Ranging Australian Pinniped Pups

Mariel Fulham,Michelle Power,Rachael Gray

doi:10.3389/fmars.2020.571171

Mariel Fulham, Michelle Power + Show 1 more

Open Access

https://doi.org/10.3389/fmars.2020.571171

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Abstract

Anthropogenic activities and pollution are impacting marine environments globally. This has resulted in increasing numbers of human-associated phylotypes of Escherichia coli, an indicator of faecal contamination, being found in both aquatic environments and upper trophic marine mammals that are 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. Faecal samples (n = 964) 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. Further 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.

Highlights

The contamination of the marine environment with atypical microorganisms as a result of anthropogenic pollution poses unknown risks to both marine wildlife and the wider ecosystem (Oates et al, 2012; Baily et al, 2015)
E. coli was detected in 842/963 (87.3%) fecal samples collected from N. cinerea, A. p. doriferus, and A. forsteri pups
There was no significant difference in E. coli phylotypes across species (p = 0.055), sampling sites (p = 0.437) or breeding season at colonies sampled over multiple breeding seasons; Seal Bay (p = 0.272), Olive Island (p = 0.199), Seal Rocks (p = 0.880), and Cape Gantheaume (p = 0.076) (Figure 3)

Summary

Introduction

The contamination of the marine environment with atypical microorganisms as a result of anthropogenic pollution poses unknown risks to both marine wildlife and the wider ecosystem (Oates et al, 2012; Baily et al, 2015) Fecal coliforms such as Escherichia coli are used globally as indicators of anthropogenic fecal contamination and as a measure of pollution of waterways and coastal ecosystems (Beversdorf et al, 2007; Schaefer et al, 2011; Ahmed et al, 2016). Escherichia coli in Pinniped Pups them opportunistic pathogens that can cause a range of diseases in multiple host species, including urinary tract infections, neonatal meningitis and septicemia (Russo and Johnson, 2000; Mora et al, 2009; Clermont et al, 2011). Many clinically relevant strains of E. coli that have the potential to cause extraintestinal disease in humans, domestic animals and birds belong to phylotype B2 (Johnson and Russo, 2002; Clermont et al, 2014)

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