Physiological characterisation of Corynebacterium uterequi associated with pregnancy complications in mares.

This study investigates the potential role of Corynebacterium uterequi, a bacterium, in causing pregnancy complications in mares, including infertility and early embryonic loss, in the Western Cape, South Africa, through various experimental approaches.

Background and Objectives

• The study emerges from an observed increase in cases of equine infertility and early embryonic loss in the Western Cape of South Africa.
• The research aimed to explore the physiological characteristics and potential pathogenicity of the Corynebacterium uterequi bacterium, which was often isolated from the uteri of infected mares, indicating potential association with the reproductive problems.
• The pathogenic potential of the bacterium was investigated by looking at its environmental stress tolerance, enzyme activity, antibiotic susceptibility, and the ability to form biofilms – a community of bacteria that adhere to each other on a surface and are typically more resistant to treatments.

Methods

• Five mares suffering from reproductive issues were selected for the study, and Corynebacterium uterequi was isolated from their uteri.
• Histopathological analyses and cultures of uterine swabs were carried out to determine the bacterium’s physiology in these mares, revealing several forms of endometritis (inflammation of the uterine lining).
• Other tentatively identified C. uterequi isolates from the urogenital tracts of mares with a history of pregnancy complications were collected and subsequently identified using molecular techniques.

Results

• The findings suggested that C. uterequi possesses several characteristics linked to virulence, including trypsin and urease activity, and the ability to form weakly adherent monoculture biofilms.
• Some isolates showed resistance to the antibiotic trimethoprim-sulfamethoxazole.
• It appeared that C. uterequi might be associated with the onset of equine pregnancy complications and the ability to form biofilms indicated a potential for causing persistent infection.

Conclusion and Future Directions

• The study provided preliminary insights into the general physiology and potential pathogenicity of C. uterequi, suggesting it might play a role in equine pregnancy difficulties. More significantly, the ability to form biofilms suggests a potential for chronic infection.
• However, more research is needed to conclusively implicate C. uterequi as an equine pathogen and to fully understand its role in pregnancy complications in mares.