Co-infection of the Siberian hamster (Phodopus sungorus) with a novel Helicobacter sp. and Campylobacter sp

Abstract

We report the isolation of a novel helicobacter isolated from the caecum of the Siberian hamster (Phodopus sungorus). Sequence analysis showed 97% sequence similarity to Helicobacter ganmani. In addition, we report the co-infection of these Siberian hamsters with a Campylobacter sp. and a second Helicobacter sp. with 99% sequence similarity to Helicobacter sp. flexispira taxon 8 (Helicobacter bilis), a species isolated previously from patients with bacteraemia. Gross necropsy and histopathology did not reveal any overt pathological lesions of the liver and gastrointestinal tract that could be attributed to the Helicobacter or Campylobacter spp. infections. This is the first helicobacter to be identified in the Siberian hamster and the first report of co-infection of Helicobacter spp. and Campylobacter sp. in asymptomatic Siberian hamsters.

Fig. 1.. Photomicrographs of liver (a) and caecum (b) from a study Siberian hamster. The liver displayed a normal hepatic lobular histology, with observable portal triads (p.t.) and central veins (c.v.), and minimal to no evidence of inflammation, fibrosis or neoplasia. Similarly, the caecum also displayed normal histology, with the mucosa containing normal intestinal glands of regular height, with minimal inflammation, fibrosis or neoplasia. Additionally, the remainder of the gastrointestinal tract (including non-glandular stomach, glandular stomach, small intestines and colon) and gallbladder were also histologically normal (not shown). Warthin–Starry-stained sections also failed to reveal the presence of any spiral bacteria in these sections. Overall, these photomicrographs are representative of the gastrointestinal tracts and hepatobiliary system in all the Siberian hamsters examined in this study, except for the presence of a squamous papilloma in the non-glandular stomach in one hamster, and hemangiosarcoma in the liver of another hamster. H&E stain. Bars, 100 µm (a); 50 µm (b).

Fig. 2.. Phylogenetic trees of 16s rRNA gene sequences showing the relationship of the helicobacter (Fig. 2a) and campylobacter (Fig. 2b) isolates in the present report (arrows) to previously sequenced isolates. GenBank accession numbers for the sequences used are shown. Bars, nucleotide substitutions per site.