Alterations in conjunctival bacteria and antimicrobial susceptibility during topical administration of ofloxacin after cataract surgery in dogs

OBJECTIVE To evaluate changes in conjunctival bacteria and antimicrobial susceptibility of bacteria after cataract surgery in dogs. ANIMALS 16 client-owned dogs. PROCEDURES Samples for aerobic and anaerobic culture were obtained from the conjunctival fornices of both eyes of dogs 24 hours before (week 0) and 1, 3, and 6 weeks after cataract surgery. Topical administration of ofloxacin (every 6 hours) was initiated 12 hours before surgery and continued for 3 weeks. In vitro antimicrobial susceptibility was determined by Kirby-Bauer disk diffusion and a commercially available test for ofloxacin. RESULTS Frequency of positive culture results was significantly higher at week 6 than at weeks 0 and 1. Bacterial load was more likely to be moderate or high at weeks 3 and 6 than at weeks 0 and 1. The most frequently cultured organism was Staphylococcus pseudintermedius (21/78 [26.9%]), followed by coagulase-negative Staphylococcus spp (19/78 [24.4%]). Staphylococcus pseudintermedius was the organism most frequentl...