First bovine and ovine isolations of Shiga toxin-producing Escherichia coli O103:H2 in Australia.

Abstract

The Escherichia coli serotype O103:H2 was first reported in 1971 as associated with neonatal lapine colibacillosis. 1 Many studies since have shown that this E coli serotype can be considered as a rabbit enteropathogenic E coli (RDEC) and it has been used as an animal model to study the pathogenesis of human enteropathogenic E coli (EPEC). It has been demonstrated that RDEC O103:H2 strains isolated from weaned rabbits with severe diarrhoea can cause the attachingeffacing lesions characteristic of both EPEC and enterohaemorrhagic E coli (EHEC).2 More recently there have been a number of reports from around the world of human cases of both bloody diarrhoea (BD) and haemolytic uraemic syndrome (HUS) caused by EHEC O103:H2 including reports from Germany, 3 the USA 4,5 as well as an outbreak in France. 6 There continue to be many reports of its isolation from both healthy cattle 5,7-9 as well as from cattle with diarrhoea. 10 However, O103:H2 has never previously been reported in Australia despite extensive serotyping of the different EHEC isolates cultured from cases of human disease and livestock. Faecal samples from four 6-week-old calves and a single faecal sample from a sheep were submitted for bacteriological examination. The calves had a bloody scour and the sheep was laterally recumbent with a slight scour, and had recently been drenched. All samples were cultured for salmonella using Muller-Kaufmann Tetrathionate and Rappaport-Vassiliadis Enrichment broths (Oxoid, Basingstoke), for yersinia using Yersinia Selective agar (Oxoid), and were also directly