Abstract
Purpose :
Contact lens cases become contaminated with bacteria during use and this can lead to corneal infiltration or infection. A novel contact lens disinfection solution containing Povidone Iodine (PI) has been recently introduced. The study evaluated the solution’s antimicrobial efficacy against ocular bacterial strains in planktonic form and following biofilm formation in the lens case.
Methods :
The antimicrobial efficacy of the MPDS against an ocular strain of P.aeruginosa (071), S. aureus (031) S.epidermidis (019) and an ATCC strain of S. marcescens (ATCC 13880) was determined according to ISO 14729:2001. Bacterial biofilm was then grown on contact lens cases for 24 hours and numbers of bacteria in biofilm calculated by plate counting. Other biofilm-loaded lens cases were disinfected for 4 hours (minimum recommended disinfection time) and then either recapped wet, air-dried, or tissue wiped and air-dried. The efficacy of these steps in removing the bacterial biofilm was evaluated by plate counting.
Results :
The PI solution performed exceptionally well against planktonic forms of all the bacterial strains tested. No viable organisms were recovered after the minimum recommended disinfection time. There were 7.9 ± 0.7 and 6.6 ± 2.8 log units of gram-negative and gram-positive bacteria respectively in untreated lens cases. The PI solution was effective in removing bacterial biofilm; air-drying or tissue wiping and air-drying the lens case was very effective in reducing biofilm (71%, p<0.001) while recapping the lens case wet removed 55% of the bacterial biofilm (p<0.001).
Conclusions :
This study has shown that ocular strains of bacteria are susceptible to povidone iodine in planktonic and biofilm form. The results also highlight the importance of air-drying on lens case hygiene.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.