Antibiotic resistance patterns of ocular surface bacterial flora

Background: Post operative intraocular infection (endophthalmitis) is a rare but devastating complication. The present study aimed to determine the antibiotic susceptibility pattern of ocular surface bacterial flora isolated preoperativelyfrom patients undergoing intraocular surgery. Materials and methods: In a prospective study, 269 patients scheduled for anterior segment surgeries, were enrolled, for whom lid and conjunctival cultures were obtained on the day of surgery before application of povidone – iodine or antibiotic drops. Bacterial isolates were identified and tested for antibiotics susceptibility using Kirby-Bauer discdiffusiontechnique. Results: Of 269 studied eyes, 127(47.2%) were male. In 101 (37.5%) cases bacterial growth was positive. Isolated bacteria in order of frequency were coagulase negative staphylococci (CNS) (90.0%), coagulase positive staphylococci (CPS) (4%), diphteroid (3%), gram negative bacillus (2%) and streptococci (1%). Totally, 95% of coagulase negative staphylococci were susceptible to vancomycin, amikacin and gentamicin. Less than 70% of isolated CNS were sensitive to ceftriaxon, tetracyelin, erythromycin, oxacillin, cotrimaxazole, and penicillin. Conclusion: Preoperative ocular surface isolates of CNS seems to be most sensitive to vancomycin, amikacin and gentamicin. Thus, preoperative application of these medications into ocular surface is suggested.