Antibacterial effect of povidone iodine disinfectant and antibiotic eye drops before cataract surgery

Abstract

Objective: Investigate the distribution of bacteria in the conjunctival sac of two groups of cataract patients with different preoperative aseptic treatments, and compare the clinical effects of 0.5% povidone-iodine (PI) and antibiotic eye drops on killing conjunctival sac bacteria.

Methods: 400 cases of patients (400 eyes) who underwent cataract surgery in the Department of Ophthalmology of Baogang Hospital in Inner Mongolia from October 2019 to October 2020 were selected in a randomized controlled study. They were randomly divided into the experimental group (group A) and the control group (group B), with 200 cases in each group. Group A: the patients were given Gatifloxacin Eye Gel (3 times/day, 1 drop/time) combined with Diclofenac Sodium Eye Drops (4 times/day, 1 drop/time) before the operation; 0.5% PI was administered to irrigate the conjunctival sac, with 0.9% Sodium
Chloride Injection washing after 3 min; 0.5% PI was administered to irrigate the conjunctival sac after operation. The corneal epithelium was observed after each irrigation. Group B: the patients were given Gatifloxacin Eye Gel (3 times/day, 1 drop/time) combined with Diclofenac Sodium Eye Drops (4 times/day, 1 drop/time) 2 days and 1 day before the operation; 0.9% Sodium Chloride Injection was administered to irrigate the conjunctival sac before and after surgical disinfection. Conjunctival sac specimens were collected for bacterial culture 2 hours before the operation, after irrigation, and after the procedure. The positive rate and the distribution of bacteria were compared between the two groups.

Results: The difference in the positive rate of bacteria in the conjunctival sac between the two groups at different time points had a statistical significance (χ² = 11.498, p < .022). Conjunctival sac specimens were collected on admission and 2 hours before the operation. There was no significant difference in the pathogens with positive results between the two groups (p = .955; p = .073); there was a substantial difference in the distribution of positive pathogens between the two groups before and after surgical disinfection (p < .001); there was a significant difference in the distribution of pathogens between the two groups after the operation (p = .005). For Staphylococcus epidermidis, Corynebacterium, Enterococcus faecalis, Streptococcus, and other Gram-positive bacteria, there was a significant difference in the disinfection methods between the two groups at different time points (p < .001); for Staphylococcus aureus, Gram-positive cocci, and Gram-negative bacteria, there was no significant difference in the disinfection methods between the two groups at different time points (p = .113; p = .224; p = .146). There was no significant difference between the two groups with 0-10 and 101-1000 bacterial colonies at different time points (p = .370 and .071, respectively). When there were 11-100 bacterial colonies, there was a significant difference between the two groups at different time points (p < .001). There was no significant difference in corneal epithelial injury between the two groups at other time points (χ² = 4.133, p = .127).

Conclusions: The combination of 0.5% PI disinfectant and antibiotic eye drops can effectively reduce the bacterial load of the conjunctival sac before operation. At the same time, it is safe and effective to irrigate the conjunctival sac with 0.5% PI disinfectant before the procedure.