Molecular characterisation of Salmonella enterica serovar Typhimurium and Campylobacter jejuni faecal carriage by captured rangeland goats

Western Australian rangeland goats were surveyed for faecal carriage of Salmonella enterica and Campylobacter spp. Faecal samples were collected from 125 goats on four occasions. The first sample was collected immediately upon arrival at a commercial goat depot (feedlot). Subsequent samples were collected at one month intervals thereafter. Frequency of detection and faecal carriage intensity were determined using qPCR targeting the S. enterica outer membrane protein (ompF) and Campylobacter spp. purine biosynthesis gene (purA). Salmonella enterica were identified in 40/500 of faecal samples, with S. enterica faecal carriage detected in 30% (38/125) goats over the duration of the study. Campylobacter spp. were identified in 12/500 of samples, with Campylobacter spp. detected in 10% (12/125) goats over duration of the study. Frequency of detection was highest at the first sample collection for both S. enterica (26%) and Campylobacter spp. (8%). Repeat detection of Salmonella was observed for only a single goat (0.8%). Salmonella qPCR positive samples were characterised at ompF and invA genes as S. enterica. Further characterisation at STM2755 and STM4497 genes confirmed the isolates were S. enterica serovar Typhimurium. Characterization at the 16S rRNA and hippuricase (hipO) genes revealed all Campylobacter spp. positive samples were C. jejuni. This study demonstrates that qPCR can be used for rapid identification of faecal carriage in goat faecal samples and showed evidence of carriage of zoonotic S. Typhimurium and C. jejuni by captured rangeland goats. The findings have implications for management of goats at abattoirs and in confined feeding facilities.