Diversity and relatedness of Shiga toxin-producingEscherichia coliandCampylobacter jejunibetween farms in a dairy catchment

Abstract

SUMMARYThe aim of this study was to examine the population structure, transmission and spatial relationship between genotypes of Shiga toxin-producingEscherichia coli(STEC) andCampylobacter jejuni, on 20 dairy farms in a defined catchment. Pooled faecal samples (n= 72) obtained from 288 calves were analysed by real-time polymerase chain reaction (rtPCR) forE. coliserotypes O26, O103, O111, O145 and O157. The number of samples positive forE. coliO26 (30/72) was high compared toE. coliO103 (7/72), O145 (3/72), O157 (2/72) and O111 (0/72). EighteenE. coliO26 and 53C. jejuniisolates were recovered from samples by bacterial culture.E. coliO26 andC. jejuniisolates were genotyped using pulsed-field gel electrophoresis and multilocus sequence typing, respectively. AllE. coliO26 isolates could be divided into four clusters and the results indicated thatE. coliO26 isolates recovered from calves on the same farm were more similar than isolates recovered from different farms in the catchment. There were 11 different sequence types ofC. jejuniisolated from the cattle and 22 from water. An analysis of the population structure ofC. jejuniisolated from cattle provided evidence of clustering of genotypes within farms, and among groups of farms separated by road boundaries.