Molecular typing and anti-microbial susceptibility of clinical isolates of Streptococcus equi ssp. zooepidemicus from equine bacterial endometritis.

The research was conducted to analyse the genetic diversity and responses to antibiotics exhibited by 65 strains of the bacterium Streptococcus equi ssp. zooepidemicus, isolated from horses affected by endometritis. It was found that they were largely susceptible to certain antibiotics, and displayed low genetic relatedness and a high level of diversity.

Anti-Microbial Susceptibility Analysis

• The researchers studied how 65 different strains of Streptococcus equi ssp. zooepidemicus responded to various antibiotics. This bacteria was obtained from horses displaying symptoms of endometritis (inflammation of the uterus lining).
• The method used for this assessment was disk agar diffusion, a common technique in microbial studies where bacteria are exposed to antibiotics on a dish and the zone of inhibition (area where the bacteria cannot grow) is measured.
• The antibiotics tested in this research include beta-lactams, enrofloxacin, trimethoprim-sulfamethoxazole, and gentamicin. The results show that the bacterial strains were generally susceptible to these antibiotics, suggesting they could be effective in treating endometritis caused by these bacteria.

Genetic Diversity of Streptococcus equi ssp. zooepidemicus Strains

• The researchers also studied the genetic diversity of the 65 bacterial strains using pulsed field gel electrophoresis (PFGE). This is a technique used to separate large pieces of DNA so they can be studied and compared, providing an overview of the bacterial strains’ genetic structures.
• The results showed that there was a great variety of genetic profiles among the strains. Specifically, 56 different macrorestriction profiles (genetic makeups) were identified, suggesting a high level of diversity.
• The strains also showed a low level of genetic relatedness, meaning they had few similarities in their genetic structures. This could potentially mean they evolved separately and have adapted to different environmental conditions or hosts.