Normal conjunctival flora and their antibiotic sensitivity in Omanis undergoing cataract surgery

To evaluate the normal conjunctival flora and to ascertain their sensitivity to antibiotics.

Prospective study was undertaken with 56 patients scheduled for cataract surgery. In each of these patients, conjunctival swab was taken from both eyes before instilling any antibiotic drops or local anesthetics and were sent for culture sensitivity by inoculating the samples in blood agar plates. The un-operated eyes served as controls for the study. The results were tabulated and analyzed by applying confidence intervals at 95% confidence limits.

Of the 112 eyes studied, positive cultures were obtained from 54 eyes (48.3%) preoperatively, and included both operated and control eyes. Coagulase-negative staphylococcus was isolated in 44 eyes (81.5%). Maximum sensitivity was found with vancomycin, gentamycin, chloramphenicol, and ciprofloxacin and maximum resistance with fusidic acid, penicillin, and oxacillin.

We conclude that coagulase-negative staphylococcus are the most common bacteria isolated from the conjunctival sac, and vancomycin followed by gentamycin and ciprofloxacin are most effective against normal conjunctiva l flora, and fusidic acid the most ineffective of all the antibiotics tested.