Elsevier

Veterinary Microbiology

Volume 101, Issue 4, 6 August 2004, Pages 235-243
Veterinary Microbiology

Fecal shedding of Helicobacter spp. by co-housed Australian sea lions (Neophoca cinerea) and Australian fur seals (Arctocephalus pusillus doriferus)

https://doi.org/10.1016/j.vetmic.2004.03.022Get rights and content

Abstract

With the emergence of Helicobacter species as agents of gastrointestinal disease within a broad range of animal hosts, there is growing awareness of the need to identify such species and the potential role(s) they play within the intestine. Of interest in this study are captive seals and sea lions, where close proximity to one another may enhance the transmission of pathogens, in particular Helicobacter. The feces of several captive Australian sea lions and Australian fur seals were assessed for the occurrence of Helicobacter over 31 days. The presence of Helicobacter, detected by the polymerase chain reaction (PCR) varied over time and at times could not be detected. Helicobacter species were detected in five of the six animals examined of which two species were identified. This is the first report of Helicobacter species in captive seals and demonstrates the diversity and potential role(s) they may play in the gut of these animals.

Introduction

Helicobacter species are ubiquitous colonizers of the gastrointestinal system (Solnick and Schauer, 2001) and have been found to occur in both humans and a broad range of animal hosts including domestic cats and dogs (Jalava et al., 1998), captive cats (Eaton et al., 1993), cattle (De Groote et al., 1999), pigs and birds (Dewhirst et al., 1994), rodents (Lee et al., 1992), sheep (Dewhirst et al., 2000), primates (Bronsdon et al., 1991), and marine mammals (Harper et al., 2002, Harper et al., 2003). To date 24 species have been formally recognized and have often been associated with conditions of gastric and/or enterohepatic disease including gastroenteritis, gastric ulcers, hepatitis and cancer (for a review, see Fox and Lee, 1997, Solnick and Schauer, 2001). However, not all Helicobacter species are considered pathogenic and instead may form part of the host’s indigenous intestinal microflora (Simmons et al., 2000). The emergence of disease may also be due to host-dependent factors (Cover, 1997) or the infection of the host with species that do not usually colonize its gut (Solnick and Schauer, 2001).

The pinniped species Neophoca cinerea (Australian sea lions) and Arctocephalus pusillus doriferus (Australian fur seals) are found predominantly within the southern waters of Australia (Bryden et al., 1998, Gales et al., 1994) and are often featured in oceanariums. The maintenance of such animals often entails widespread medical problems since disease, particularly that of the gastrointestinal system, is common (Lauckner, 1985). With the detection of Helicobacter species as agents of disease in cetaceans (Harper et al., 2002) and, more recently, in wild harp seals (Harper et al., 2003), its occurrence in captive animals may add to the already pervasive medical problems associated with the husbandry of these animals (for a review see Higgins, 2000, Lauckner, 1985). However, its occurrence in the captive host has not been previously reported.

This paper reports on the occurrence of Helicobacter species within the feces of several captive Australian sea lions (N. cinerea) and Australian fur seals (A. pusillus doriferus) using 16S rRNA PCR analysis. The occurrence of Helicobacter species within the feces of each animal was examined over a 31-day period using PCR and sequence analyses. Of the animals investigated only one (“Duran”) was previously diagnosed with a suspected Helicobacter related infection, all other animals were asymptomatic.

Section snippets

Sample collection

Fecal samples were collected from the holding pens of five individual seals (one fur seal, four sea lions) over a 31-day period. At each sampling period, approximately 20 g of fecal material from each animal was obtained, placed in an individual sterile collection vial and stored immediately on ice. Samples were collected from individuals within 12 h of defecation. Experiments showed that the recovery of template DNA and its amplification was not affected over this time period (data not shown).

Preparation of samples for DNA extraction

PCR sensitivity

To establish the sensitivity of the PCR assay, cells of H. pylori (106 to 101) were added to PBS and fecal samples (Fig. 1). DNA extracts of these samples were subjected to PCR and products were observed in samples of PBS spiked with as little as 104 cells. Taking into account the fraction subjected to PCR (1/125th) this represents a limit of detection of approximately 102 cells. Similarly, in fecal samples, a relatively strong PCR signal was observed with a limit of detection of 102 cells. The

Discussion

This paper reports on the occurrence of Helicobacter species within the feces of captive Australian sea lions (N. cinerea) and Australian fur seals (A. pusillus doriferus). Depending upon the individual animal, the presence of Helicobacter (as indicated by the amount of PCR product) was either variable or consistent over the 31-day period and in some cases occurred below the limits of detection (102 cells g−1). We cannot ascribe this variability to variations in amplification or to a variation in

Acknowledgements

The authors thank UnderWater World (Mooloolaba, Australia) and its staff for their support and cooperation in the collection of samples, in particular Greg Elks, Kristy Rychdalvalsky, Chris Groot, Lucas Robinson, Brad McKenzie and Malcolm Westwood. We also thank Melissa Wos, Jeffrey Argo and Alexis Oxley for their contributions. This work was supported by the School of Biological, Cellular and Molecular Sciences, University of New England, Armidale and the National Marine Science Center, Coffs

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