Comparison of 5% povidone-iodine solution against 1% povidone-iodine solution in preoperative cataract surgery antisepsis: a prospective randomised double blind study

Abstract

Background/aim: Povidone-iodine (PI, Betadine) is routinely used as a preoperative topical antiseptic in cataract surgery as it has been shown to reduce the incidence of postoperative endophthalmitis. However, the concentration used clinically is variable. In vitro studies have shown that PI is paradoxically more effective at lower concentration. This study was undertaken to determine if this effect was reproducible in vivo. Methods: A prospective randomised double blind study was carried out in the ophthalmic theatre in a district general hospital. 105 patients attending for routine cataract surgery were randomly allocated to have their conjunctival fornices irrigated preoperatively with either PI 1% (group A) or PI 5% (group B). Conjunctival swabs were taken, in identical fashion, both before and 1 minute after irrigation. The number and species of bacterial colonies cultured from each swab was counted. The difference in the median number of bacterial colonies from pre-irrigation to post-irrigation cultures was then compared between the groups. Results: Bacterial cultures were gained from 100 patients (33 male, 67 female, mean age 74 years, range 30-95 years). Group B (5% PI) showed a decrease in median colony forming units (CFU) preirrigation from 100 to 40 CFU post-irrigation (a drop of 60%). This was greater than in group A (1% PI) where the reduction was 120 CFU pre-irrigation to 100 CFU post-irrigation (a drop of 16.7%) (Mann-Whitney test, p<0.05). At higher initial bacterial loads (CFU pre-irrigation >1000), the difference in median between the two groups became larger as the number of pre-irrigation bacteria increased. In group B pre-irrigation CFU reduced from 3340 to 110 post-irrigation (a drop of 96.7%) compared with group A: 5000 CFU pre-irrigation to 3000 post-irrigation (a drop of 40%) (Mann-Whitney test, p=0.0014). Conclusion: Despite in vitro evidence of higher bactericidal efficacy of PI at more dilute concentrations, 5% PI is more effective than 1% PI in decreasing the human conjunctival bacterial flora in vivo, particularly in the presence of heavier initial bacterial load.

A prospective study demonstrating the effect of 5% povidone-iodine application for anterior segment intraocular surgery in Paraguay

“…A United Kingdom study of 100 patients, which compared the effects of 1% and 5% povidone-iodine solutions, demonstrated that irrigation with the 5% solution led to a 60% reduction in colony forming units, compared to a 16.7% reduction using the 1% solution. This result was significant (p<0.05), and the difference more evident when the initial bacterial load was higher (13) . In our study, irrigation of the conjunctival fornices with 5% povidone-iodine achieved a major reduction (60.8%) in conjunctival flora.…”

The effect of povidone iodine flush versus drops on conjunctival colonization before intravitreal injections

“…Kiffney et al showed that reducing full strength 10% povidone iodine by half greatly reduced ocular irritation while maintaining bactericidal efficacy [15]. Diluting the strength of povidone iodine any further results in less bactericidal efficacy [6]. With the recent increase in the number of intravitreal injections performed for different retinal disorders, identifying the most effective application technique of povidone iodine is of significant importance.…”

Daya antibakteri obat kumur chlorhexidine, povidone iodine, fluoride suplementasi zinc terhadap, Streptococcus mutans dan Porphyromonas gingivalis (Antibacterial effect of mouth washes containing chlorhexidine, povidone iodine, fluoride plus zinc on Strep

“…Jumlah bakteri akan berpengaruh terhadap daya kerja povidone iodine, dimana jumlah iodine bebas yang dilepas sebagai bahan aktif bakterisidal akan berkurang efektifitasnya dengan jumlah bakteri awal yang tinggi. 6 Poviodone iodine memiliki sifat anti bakteri utamanya melalui mekanisme dimana povidone membawa senyawa iodine bebas masuk menembus membran sel. Senyawa iodine memiliki sifat yang sitotoksik sehingga mampu membunuh sel bakteri.…”