Microbiological Investigations of Equine Infections in Relation to Oxidative Stress Markers

31 Abstract: This study aimed to investigate genital tract causes of repeat breeding in equine stable, digestive and respiratory infections, stress and oxidative stress. Vaginal, uterine, nasal and rectal swabs were collected from horses. Blood serum and seminal plasma samples were collected from repeat breeding animals before and after receiving treatment. Microbiological studies revealed that E. coli (39%), S. aureus (14.63%) and E. faecalis (9.75%) were isolated from repeat breeding mares. S.aureus (30.09%) and E.coli (9.52%) were isolated from respiratory disorders. Enteropathogenic gene (sfa gene) was detected in four strains (66.67%) of six E.coli isolated from vaginal swabs of repeat breeding mares. Our study indicated that E.coli strains which hinder sfa gene might play an important role in repeat breeding mare. Real time PCR results confirmed positive Pseudomonas isolates and showed that E. coli isolates were negative for vtx1 and vtx2.Cortisol increased in mares with reproductive tract and mixed reproductive-respiratory tract infection compared to other healthy animals. Ascorbic acid levels declined significantly in stallions' serum with respiratory tract infection and mares with reproductive-respiratory tract infection. Glutathione levels decreased in diseased animals than control cases. Cortisol and all antioxidant markers improved after treatment with the selected antibiotic. In conclusion, E.coli was the most common pathogens recovered from subclinical endometritis. However, as antimicrobial resistance changes over time, susceptibility assays should aid antimicrobial drug selection. It is recommended to supply horses undergo breeding with some antioxidants such as ascorbic acid to improve their antioxidant status.