Prevalence of Salmonella spp. and environmental factors in healthy & and colic horses

Salmonellosis is an important enteric or systemic infection caused by the bacterium Salmonella affecting horses. There are multiple sources of infection which begins with fecal-oral transmission. Asymptomatic horses are capable of shedding Salmonella organisms, which is a risk to other resident animals and contaminating the environment. Environmental contamination is an important source of nosocomial Salmonella infections in horses in stables and those hospitalised at equine referral centres or clinics. This study has three objectives; 1) to determine the prevalence of Salmonella shedding in horses presented with colic to the University Veterinary Hospital (UVH), Universiti Putra Malaysia, 2) to determine the prevalence of salmonellosis of healthy horses and the extent of environmental contamination of equine stables in Peninsular Malaysia, and 3) to evaluate the extent of environmental contamination with Salmonella at the Large Animal Ward (LAW), UVH. All horses that were sampled were more than one year of age, indiscriminate sex, and breed. Fresh fecal samples were obtained from the rectum of the horse as a grab sample, and sampling was performed daily until a minimum of three faecal samples were obtained. For objective 2; the stall environment of the selected horses was sampled, and a sterile gauze was used to swab areas of the walls, feed and water buckets. For objective 3; 135 environmental samples were collected from areas within LAW-UVH, such as wards, flooring, walls, buckets, and equipment, using moistened sterile gauze swabs. Standard aerobic bacterial culture was selective for Salmonella, and antimicrobial sensitivity testing was performed for all samples. For all faecal samples, polymerase chain reaction (PCR), using genus-specific primers, and positive results were indicated by a fluorescent 496-bp band. Result section: For objective 1; all horses presenting with colic were negative for Salmonella spp. with bacterial culture, and the prevalence using PCR was 60% (6/10). For objective 2; the prevalence of salmonellosis in healthy horses was 2.4% by bacterial culture and 18.3% by PCR. The prevalence of environmental contamination in the equine stables with Salmonella was 1.6%. Antimicrobial sensitivity testing of the three positively identified faecal samples revealed a similar antimicrobial resistance profile (penicillin-enrofloxacin), while the four positive environmental samples revealed two antimicrobial resistance profiles (penicillin-gentamicin-enrofloxacin & penicillin-streptomycin-gentamicinenrofloxacin). For objective 3; the extent of environmental contamination in the hospital was 4.4% (6/135), where Salmonella was successfully isolated from floorings (3/16, 18.75%), walls (1/16, 6.3%), a water bucket (1/32, 3.1%) and cleaning equipment (1/10, 10%). The results of this study have confirmed the presence of Salmonella shedding in horses that present with colic, as well as healthy horses residing in equine stables. Additionally, the environments of both equine stables (1.6%) and the hospital premises (4.4%) are contaminated with Salmonella bacteria.

Text 122351.pdf Download (1MB) Official URL or Download Paper: http://ethesis.upm.edu.my/id/eprint/18567

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