Water as a reservoir for Campylobacter jejuni infection in cows studied by serotyping and pulsed-field gel electrophoresis (PFGE).

The occurrence of campylobacters was studied in the faecal samples of a dairy herd with about 20 animals and in the lake which was their source of drinking water during the grazing period from June to September. Of the total of 141 faecal samples studied, 0-21% were found to be positive for C. jejuni at various sampling times throughout the year. More cows were found to be campylobacter-positive in summer or in autumn after the grazing period than after the winter, when the animals were inside and their drinking water source was municipal chlorinated tap water. C. jejuni was isolated from most of the lake water samples. Serotyping with heat stable antigens and molecular typing with PFGE using SacII- and SmaI-digested DNA revealed that an animal that was permanently infected with C. jejuni sero-/PFGE-type PEN 0:6, 25/I/ND most probably contaminated the lake water in summer 1987. This was the only sero/PFGE-type isolated from the lake water in summer and autumn 1987 and in spring 1988. This sero/PFGE-type was also isolated from four other cows in autumn 1987, suggesting that lake water was the source of the infection. This study is first to employ molecular methods to assess the possible role of contaminated drinking water in the transmission of campylobacter infection within a dairy herd.