Twelve ejaculates were collected in the most aseptic manner and distributed in seven treatments (control group T1). Semen were inoculated with S. aureus (T2, T3 e T4) or E. coli (T5, T6 e T7) in three concentrations (5 x 10(5), 5 x 10(6) and 5 x 10(7) CFU/ml). The sperm motility, the percentage of normal apical range (NAR), the pH and the number of colony unit former (CFU/ml) of bacteria, for 96 hours, were evaluated. The bacterial development was decreasing during the first 96 hours. Except for the treatment with the inoculation of 5 x 10(7) CFU of E. coli/ml, there was no significant effect of the bacteria on the sperm motility (p>0.05). Also, there was no significant effect (p>0.05) of the S. aureus or E. coli on the percent of NAR and the pH during the 96 hours. When compared to the control group, only the inoculation of 5 x 10(7) CFU/ml of E. coli differed at the 96 hours in relation to the percentage of NAR (p<0.05). There was no correlation among the sperm motility, NAR, pH and CFU.
semen; acrosome; Escherichia coli; Staphylococcus aureus