Infectious endometritis in Arabian mares: an updated clinical investigation of uterine microbial isolates, antimicrobial sensitivities and fertility in Egypt

Abstract

The present study aimed to survey the prevalence of microbial isolates in the uterus of sub-fertile Arabian mares
and to identify their existing antimicrobial sensitivities. In addition, to evaluate the efficacy of antimicrobial therapy
based on the fertility outcomes determined by sonographic pregnancy diagnosis. Double guarded uterine swabs were
collected from (barren) Arabian mares during mid-estrus. Based on the laboratory findings of microbial culture and
antimicrobial sensitivity, mares were treated, inseminated and tested for pregnancy two weeks after ovulation. The
predominant microbial isolates were Beta-hemolytic streptococci (BHS) (38.9%), Escherichia coli (E. coli) (33.3%),
Staphylococcus aureus (S. aureus) (20.4%) and Candida albicans (C. albicans) (7.4%). Moreover, the sensitivity of BHS and
E. coli isolates to cefepime was significantly higher (P< 0.05) than the rest of the antimicrobials (57.14% and 55.56%,
respectively). However, S. aureus isolates did not display a significant difference regarding their antimicrobial
sensitivities, its sensitivity to amoxicillin-clavulanic acid was the highest (36.37%). On the other hand, fluconazole was
the favored antifungal in this study (100 % sensitivity). The pregnancy outcomes were variable depending on the type
of microbial isolate and antimicrobial treatment; for instance, cefepime resulted in the highest pregnancy rates in BHS
and S. aureus mare groups (66.67% and 100%, respectively). Interestingly, amikacin achieved the highest pregnancy
rate in the E. coli group (66.67%). In conclusion, BHS is the dominant uterine isolate in Arabian sub-fertile mares. For
most cases of bacterial endometritis, cefepime may be the antibiotic of choice and fluconazole may be the effective
therapy in the case of C. albicans infection. However, standard diagnostic and treatment procedures should be used to
minimize the emergence of antimicrobial resistance.