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

Abstract

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 3 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.

Nontyphoid Salmonella Prevalence, Serovar Distribution and Antimicrobial Resistance in Slaughter Sheep

“…In particular, nontyphoid Salmonella (NTS), which has the most significant disease burden and foodborne deaths worldwide, in carcasses, internal organs and lymph nodes of slaughter sheep entering the food chain could be a substantial threat to public health (EFSA and ECDC, 2018). Common practices, such as transport, consignment in multiple groups before sale, and feed and water deprivation, could cause stress and increased shedding of the pathogen prior to slaughter (Al-Habsi et al, 2018;Yang et al, 2017). Thus, assessment of the NTS serovars and their antimicrobial resistances isolated from ovine carcasses is of critical value for farm-level biosafety measures and epidemiology.…”

Cryptosporidium infection is associated with reduced growth and diarrhoea in goats beyond weaning

“…The sampling protocol for this study has been previously described (Al-Habsi et al, 2017a;Al-Habsi et al, 2017b;Al-Habsi et al, 2017c;Al-Habsi et al, 2018). Briefly, male rangeland goats (n=125) were captured from a grazing property located in the Gascoyne region of Western Australia, and transported by road to a commercial goat depot (feedlot).…”

“…Screening and amplification of faecal samples (n = 500) for Salmonella and Campylobacter has been described in more detail by Al-Habsi et al (2018). Briefly, qPCR screening was performed for Salmonella targeting the outer membrane protein (ompF) and…”

“…The causes of diarrhoea and ill thrift in goats of post-weaning age are not well understood, but it is suggested that stress related to transport, overcrowding and, for wild goats, capture and domestication predispose goats to disease. Recent investigations identified faecal shedding by captured rangeland goats for a range of infections with potential veterinary and zoonotic significance, including Cryptosporidium and Giardia (Al-Habsi et al, 2017c), Eimeria (Al-Habsi et al, 2017b), Entamoeba (Al-Habsi et al, 2017a), and Salmonella and Campylobacter (Al-Habsi et al, 2018). Elucidating the impact of these infections (and especially Cryptosporidium and Giardia) on goat productivity, and specifically diarrhoea and ill thrift, for goats raised in commercial production environments would inform recommendations for best-practice management to address impacts on farm profitability and animal welfare, as well as addressing public health risks associated with zoonotic pathogens.…”