Comparison of iodine compounds and levofloxacin as postoperative instillation; conjunctival bacterial flora and antimicrobial susceptibility following cataract surgery.

PURPOSE

To compare the cleanliness of the conjunctival sac following the use of iodine compounds (PAI) and levofloxacin as postoperative eye drops.

STUDY DESIGN

A prospective open-label study.

PATIENTS AND METHODS

Either topical levofloxacin or fourfold-diluted PAI was administered for 1 week postoperatively in 128 eyes of 128 patients who underwent routine cataract surgery. Conjunctival samples were obtained at three time points: pre-surgery, 1 week postoperatively, and 1 month postoperatively.

RESULTS

The respective positive bacterial culture rates for postoperative iodine and levofloxacin were 88.1% and 85.2% pre-surgery, 71.6% and 50.8% 1 week postoperatively, and 92.5% and 86.5% 1 month postoperatively. Positive bacterial culture rates in both groups significantly declined at 1 week, and the rates returned to the baseline level 1 month postoperatively. The magnitude of reduction of DNA copy number detected by polymerase chain reaction at 1 week was larger in the levofloxacin group, although no significant differences were seen at pre-surgery or 1 month postoperatively. In the levofloxacin group, only one strain was culture positive at 1 week, however, its minimum inhibitory concentration (MIC) against S. epidermidis was high (128 µg/ml). The MIC value increased from 2.31 ± 2.19 µg/ml pre-surgery to 57.14 ± 22.34 µg/ml 1 month postoperatively, while no significant change was found in the iodine group.

CONCLUSION

Postoperative iodine and levofloxacin eye drops both reduced bacterial contamination in the conjunctival sac, with a superior level of disinfection in the levofloxacin group. However, postoperative levofloxacin eye drops enhanced the emergence of highly resistant bacteria, whereas no such development was seen in the iodine group.