Presence and distribution of fungi and bacteria in the reproductive tract of healthy stallions.

A saprophytic bacterial flora is present on the penis and the distal part of the urethra of stallions. Little is known about the fungal flora of their reproductive tract. As micro organisms play an important role in mares fertility, the aim of the study was to describe the distribution of fungi and bacteria in the normal genital apparatus of stallions. The microbic flora of the reproductive tract of 11 healthy, fertile stallions was evaluated, collecting samples from 5 different locations: urethral fossa, penis/internal lamina of the prepuce, urethra pre- and post-ejaculation, and semen. For fungal examination samples were taken on 3 different occasions (N = 165), while for bacteriologic examination samples were taken on one occasion only (N = 55). There was a statistical difference in the presence of filamentous fungi between urethral fossa or penis/prepuce (45.4%) and urethra pre- or postejaculation or semen (15.1%, 6.0%, and 0.0%, respectively). Yeasts were isolated in 9.1% of the samples, never in semen. The most represented mycelial fungi were Penicillium spp., Aspergillus spp., Scopulariopsis spp., Trichosporon spp. and Mucoracee. The proportion of samples showing a total bacterial count ≥ 10,000 colony forming units (CFU) was higher for urethral fossa than for urethra pre- or postejaculation or for semen. Some bacterial growth was always observed in all locations, including the ejaculate. Differences between sampling locations were observed also for Staphylococci, both coagulase positive and negative. Salmonella enterica Abortus equi and sulphite reducing clostridia and other pathogens (including Klebsiella spp. and Pseudomonas spp.) were never isolated. Escherichia coli and coliforms always showed a low or absent flora. These data add information to the literature.