Abstract

Aim/background- This study investigated and compared vaginal bacterial isolates and antimicrobial susceptibility patterns in apparently healthy bitches and those with genital tract infections at different stages of the oestrous cycle.
Methods- A total of 40 client-owned bitches at different stages of the estrous cycle presented to the Veterinary Teaching Hospital, University of Ibadan were included in this study. 24 were qualified to the apparently healthy group while 16 bitches qualified to the group with genital tract infections. Vaginal samples were subjected to cytology and bacteriological analysis using standard culture and biochemical techniques. Antibiotic susceptibility testing was performed by disk diffusion following CLSI guidelines. Chi-square and Fisher’s exact tests were applied to assess differences in bacterial prevalence between health groups and across oestrous cycle stages.
Results- The overall positive culture rate was 87.5% (35/40), with mixed cultures recorded in 74.3% (26/35) of positive samples. Escherichia coli (54.2% healthy vs. 56.2% infected) and Staphylococcus spp. (41.7% healthy vs. 62.5% infected) were the most prevalent organisms in both groups. Statistical analysis revealed no significant difference in the prevalence of any individual bacterium between apparently healthy and infected bitches nor in overall positive culture rates. Similarly, no significant differences in bacterial prevalence were detected across oestrous cycle stages. Corynebacterium spp. and Citrobacter spp. were isolated exclusively from infected animals during diestrus and anoestrus, respectively, though their low frequencies precluded statistical significance. Candida spp, a fungus, was isolated from one of the samples from the apparently healthy bitches. Antibiotic susceptibility testing demonstrated the highest sensitivity to fluoroquinolones (ciprofloxacin and ofloxacin), with universal resistance to amoxicillin and amoxicillin-clavulanic acid across all major isolates. Klebsiella spp. exhibited near-complete multidrug resistance.
Conclusion- The findings emphasize the importance of clinical and cytological evaluation before prescribing antibiotics, especially during breeding.

Key words: Vaginal bacteria, bitches, antibiotic resistance, oestrous cycle, proestrus, oestrus