Serpulina pilosicoli: a water-borne pathogen?

Abstract

Serpulina pilosicoli is recognised as the causative agent of intestinal spirochaetosis (IS), a diarrhoeal disease which affects a variety of vertebrate hosts including pigs, dogs, birds and humans, It is commonly isolated from the faeces of individuals in developing communities, HIV positive patients and homosexual males in western societies. Additionally S. pilosicoli has been isolated from the bloodstream of debilitated patients. In order to determine the potential sources of human contamination, water from a lake at Perth Zoological Gardens and faeces from 43 water birds frequenting the lake were examined. S. pilosicoli was isolated and identified from eight of the 43 faecal samples (18.6%) and from three of the seven (42.8%) samples of lake water. A subset of 17 faecal samples were subjected to DNA extraction and PCR after primary culture, and eight (47%) were positive for S. pilosicoli DNA. Experimentally, S. pilosicoli was shown to survive in lake water for more than one month and in tap water for from one to 14 days. A volunteer who drank 1 x 10 9 cells of an S. pilosicoli strain mixed with tap water on three successive days became colonised with the same strain. The results suggest that water contaminated with faeces containing S. pilosicoli could be a source of infection for humans and animals