Equine salmonellosis in a Dutch veterinary teaching hospital.

The research article investigates the occurrence of infection caused by Salmonella species in horses, using fecal samples from horses in a Dutch veterinary teaching hospital. The investigation focuses on the frequency of infection, the Salmonella species involved, and the antibiotics the species were sensitive or resistant to.

Methodology and Findings

• The study was carried out over two years, 1990 and 1991, involving the collection and testing of 380 fecal samples from horses suffering from diarrhoea in a teaching hospital.
• Through culturing, it was discovered that 18%, or 69 of the samples, tested positive for the presence of Salmonella species.
• In slightly over half of these positive cases (54%), the salmonellae were directly found via culture, while in the remaining cases (46%) the bacterium was found after being cultured in an enrichment medium.

Prevalence of Different Salmonella Species

• Different species of salmonellae were isolated and identified. They included: Salmonella typhimurium, S hadar, S arizona, S enteritidis, S virchow, S blockley, and S bareilly.
• S typhimurium was the most commonly isolated species in the study, with 43 samples testing positive for it.
• The other species were much less common, with S hadar, S arizona, and S enteritidis found in two to three samples, and S virchow, S blockley, and S bareilly found in one sample each.
• The types of S typhimurium identified were different in each year of the study, with phage type 200 being the predominant type in 1990, and phage types 510, 656, and 658 being most common in 1991.

Antibiotic Resistance

• The study also investigated the antibiotic resistance profiles of the different Salmonella species, analyzing 53 out of the 69 positive samples.
• The findings showed that more than half (28) of these isolates were resistant to at least three different antimicrobial agents.
• Streptomycin and tetracyclines were the drugs to which resistance was most commonly observed.
• However, most of the Salmonella isolates were susceptible to other antibiotics such as gentamicin and nitrofurantoin.

In conclusion, the study provides valuable insights into the diversity of Salmonella species affecting horses in the teaching hospital, their prevalence, and their antibiotic resistance profiles. It shows the need for continued surveillance in veterinary settings to help manage and control Salmonella infections.