Meatal recolonization in bitches.

Colonization of the urethrovaginal area precedes urinary tract infection in women. Among the potential factors limiting colonization by fecal pathogens is bacterial interference, the ability of established commensals to inhibit colonization by pathogenic bacteria. Since the microcontour of the canine distal urethra possesses microvilli like those in the vagina rather than the microplicae found at higher levels and also has similarities in cellular glycogen content the meatal area would be expected to respond to hormonal influences like the vagina. The normal canine urethrovaginal flora was determined by serial cultures. It consisted principally of Staphylococcus epidermidis, Corynebacterium and Acinetobacter-Haemophilus. Estrus produced a selective overgrowth of beta-Streptococcus and Acinetobacter-Haemophilus. A normal canine transient, Escherichia coli, and a normal resident, Corynebacterium, persisted only for a short time (4.5 days) unless inoculated during estrus, when they remained for a mean period of 70 days. In contrast, human Escherichia coli and Pseudomonas persisted only a short time, whether during anestrus (4.8 days) or during estrus (8.5 days). The commensals had returned fully by 14 days after sterilization, while those in estrus overresponded. Thus, indigenous bacteria inhibit establishment of certain foreign species in the urethra and hormones enhance the susceptibility to colonization.