The effect of season on aerobic bacterial flora of conjunctiva in the healthy horses

AbstractThe objectives of this study were to identify the aerobic bacterial flora of conjunctival sac in healthy horses and to determine the seasonal variations of these flora as well as antibiotic susceptibility of the isolates. Forty-two swabs were taken from the inferior conjunctival sac of 21 normal horses (10 stallions and 11 mares), in October, January, April, and July . The samples were inoculated on blood agar and MacConkey agar, and examined for aerobic bacteria. A total of 10 different bacterial species (3 Gram-positive, 7 Gram-negative) were recovered. Gram-positive aerobes were most commonly cultured (59.04% of all isolates). The first five predominant organisms were Bacillus cereus, Staphylococcus epidermidis, Klebsiella oxytoca, beta-hemolytic streptococci and Escherichia coli. According to the statistical analysis, the isolation frequency of B. cereus in spring, E. coli in summer and S. epidermidis in autumn were significantly more than the other seasons (p0.05). In the stallions, the isolation frequency of K. oxytoca in spring was significantly higher than the other isolates and in the mares, the frequency of S. epidermidis was significantly higher in summer (p