[Comparative plasmid profile analysis of Salmonella typhimurium var. Copenhagen strains from a Salmonella outbreak in hospitalized horses].

This research article discusses an outbreak of Salmonella disease in hospitalized horses, tracing the source to a specific strain of the Salmonella typhimurium var. Copenhagen bacteria, which the horses presumably picked up within the hospital setting.

Research Objective and Methodology

The study was conducted between April 1990 to June 1991 following an outbreak of salmonellosis in hospitalized horses. The researchers aimed to identify the cause of the high incidence of Salmonella infection, both clinical and latent, in these horses. To achieve this, they studied:

• 76 Salmonella strains from the sick, hospitalized horses
• 18 strains from horses with no clinical symptoms

The strains were characterized by serotyping and plasmid profile analysis, a method that examines the genetic material of the bacteria.

Findings

The researchers found out that 97.8% of the hospitalized horses were infected with strains of S. typhimurium var. Copenhagen from April 1990 to January 1991. These strains were closely related, as indicated by their similar plasmid patterns.

In February 1991, other strains of S. typhimurium var. Copenhagen and S. enteritidis were also detected. During this same period, different plasmid profile types of S. typhimurium var. Copenhagen along with strains of S. typhimurium, S. enteritidis and S. lexington were isolated from the control group of horses.

Conclusion

The study suggests that the high incidence of salmonellosis and latent salmonella infections in hospitalized horses was primarily due to the spread of a particular strain of S. typhimurium var. Copenhagen. It indicates that the horses likely caught this strain during their hospital stay. Hence, the findings highlight the need for strict infection-control measures in veterinary hospitals to prevent the spread of such infections.