Adherence of Brucella ovis to preimplantation ovine ova

Seventy-three zona pellucida-intact ova were collected surgically from 15 superovulated, Brucella -free mixed-breed ewes. Twenty-one groups containing one to five ova were incubated in medium containing Brucella ovis . Subsequently, seven and five groups were incubated for 24 and 4 h, respectively, at 37 degrees C in medium containing penicillin and streptomycin, while nine groups were not treated with antibiotics. All groups of ova were washed 10 times, and ova and sequential washes were cultured for the presence of B. ovis . Brucella were isolated from seven of the nine groups of nontreated ova and from the 10th wash for six of these groups. While Brucella were detected in fewer washes after antibiotic treatment, the organism was still isolated from 11 of the 12 treated groups. Results indicate that standard washing techniques are not reliable for removing B. ovis from exposed, zona pellucida-intact, ovine ova.