Conjunctival bacterial flora and antibiotic resistance pattern in patients undergoing cataract surgery

ABSTRACT

PURPOSE: To evaluate the conjunctival bacterial flora and its antibiotic resistance pattern in eyes of patients undergoing cataract surgery. METHODS: From August to October 2004, 50 patients undergoing cataract surgery in the "Fundacão Altino Ventura", Recife, Brazil, were prospectively evaluated. Conjunctival material was obtained on the day of surgery, before the application of topical anesthetic, antibiotic or povidone-iodine. The collected material was inoculated and bacterioscopic analysis was carried out. In the cases where there was bacterial growth, antibiotic susceptibility tests and cultures, for isolation and identification of the bacteria, were performed. RESULTS: Of the 50 eyes, 43 (86.0 percent) had positive cultures. The coagulase-negative Staphylococcus (CNS), found in 27 (54.0 percent) eyes, was the most frequent organism. More than 90 percent of the isolates of this bacterium were susceptible to cephalotin, vancomycin, chloramphenicol, ofloxacin and gatifloxacin; 70 to 90 percent were susceptible to gentamicin, cefotaxime, oxacillin and ciprofloxacin; and less than 70 percent were sensible to neomycin. Four (10.5 percent) of the bacterial isolates were resistant to four or more antibiotics, two of them were CNS. CONCLUSION: The most frequent bacterium in the conjunctival flora is the coagulase-negative Staphylococcus. The isolates of this organism showed low susceptibility rate to neomycin, and high susceptibility rates to cephalotin, vancomycin, chloramphenicol, ofloxacin and gatifloxacin.