Comparative efficacy of two different topical povidone-iodine 5% regimens in reducing conjunctival bacterial flora: A randomized parallel double-masked clinical trial

Abstract

IntroductionThe increasing prevalence of multi-resistant bacteria is a major public health concern. Infections acquired during ophthalmic surgery are devastating. The purpose of the current study is to compare the proportion of eyes with negative bacterial cultures on all tested media after 1 versus 3 sequential drops of povidone-iodine (PI) 5% into the inferior conjunctival fornix.MethodsPatients were randomly assigned to receive 1 (PI group) drop (at time 28 minutes) or 3 (PI plus group) sequential drops (at time 0, 20 minutes and 28 minutes) of PI 5% into the inferior conjunctival sac of one randomly selected eye. A swab culture was obtained from the inferior conjunctival fornix 5 minutes before and 30 minutes after time 0. Central corneal thickness (CCT) was measured shortly before time 0 and shortly after time 30. Conjunctival swabs were incubated aerobically in enriched Thioglycolate liquid medium (meat broth) and in three solid culture media (chocolate agar, trypticase soy agar with 5% sheep blood, and Sabouraud agar).ResultsThere was no significant difference in the proportion of negative cultures after intervention between groups (p = 0.1638). Also in the PI group (n = 59), the proportion of eyes with negative cultures after PI (79.7%) did not differ significantly from baseline (76.3%; p = 0.7539). However in the PI plus group (n = 61), the proportion of eyes with all negative cultures after PI (85.3%) was significantly higher than before PI (70.5%) (p = 0.0177). There was no significant difference in mean CCT before and after the intervention in both groups.ConclusionInstillation of 3 sequential drops of PI was associated with a significant increase in the proportion of eyes with all negative cultures, while instillation of a single drop of PI was not associated with a significant increase in the proportion of negative cultures. Further study is warranted to determine whether the difference between the PI administration regimens is also associated with differences in the rates of postoperative ocular infections.

Povidone iodine treatment is deleterious to human ocular surface conjunctival cells in culture

“…13 14 Following surgical trauma, bacterial flora isolated from patients who developed endophthalmitis were identical to those isolated from the patient's own conjunctiva and eyelid. 15 To minimise the risk of infections during surgery or ocular injections such as anti-vascular endothelial cell growth factor (VEGF) therapies, ophthalmologists apply the antiseptic povidone iodine (PI) to the conjunctival sac prior to surgery. PI concentrations from 1% to 10% for between 30 s and 10 min reduce the number of bacterial colonies cultured from conjunctiva [15][16][17][18][19][20][21] and the rate of endophthalmitis.…”

“… 13 14 Following surgical trauma, bacterial flora isolated from patients who developed endophthalmitis were identical to those isolated from the patient’s own conjunctiva and eyelid. 15 …”

“…To minimise the risk of infections during surgery or ocular injections such as anti-vascular endothelial cell growth factor (VEGF) therapies, ophthalmologists apply the antiseptic povidone iodine (PI) to the conjunctival sac prior to surgery. PI concentrations from 1% to 10% for between 30 s and 10 min reduce the number of bacterial colonies cultured from conjunctiva 15–21 and the rate of endophthalmitis. 15 22 The American Academy of Ophthalmology recommends a concentration of 5% PI to be applied prior to cataract surgery but does not recommend a specific duration or volume.…”

“…PI concentrations from 1% to 10% for between 30 s and 10 min reduce the number of bacterial colonies cultured from conjunctiva 15–21 and the rate of endophthalmitis. 15 22 The American Academy of Ophthalmology recommends a concentration of 5% PI to be applied prior to cataract surgery but does not recommend a specific duration or volume. Likewise, the European Society of Cataract and Refractive Surgeons recommends application of between 5% and 10% PI for no longer than 3 min but does not provide guidance on volume.…”

Use of an ultra-clean air flow for surgical field asepsis when performing intravitreous injections in an ambulatory surgical environment

“…In Canada and in USA, IVIs are mainly performed in the office [9], whereas in other countries IVI are limited to the operation rooms (OR) or to a sterile room with hygienic standards in order to decrease the risk of infection and EO. Important hygienic practices include hand hygiene, appropriate OR clothing, face masks for physicians and staff assisting in IVIs, the use of sterilized surgical fields, and isolation of the eyelashes and topical administration of 5% povidone-iodine 30 s before IVIs [9][10][11]. In addition, methods that may improve the quality of the OR air, such as ultraclean room ventilation, should be considered [13,15].…”