Abstract
Purpose :
Contact lens cases are often contaminated with gram negative bacteria during use which may lead to corneal infiltration or infection. Recent studies report contamination with previously unreported gram-negative bacteria such as Achromobacter xylosoxidans and Elizabethkingia meningoseptica. This study evaluated the efficacy of two multipurpose disinfectant solutions (MPDS) against these emerging pathogens in planktonic form and following biofilm formation in the contact lens cases.
Methods :
The antimicrobial efficacy of two MPDS, Biotrue and Cleadew, against one strain each of strain of Achromobacter xylosoxidans (001) and Elizabethkingia meningoseptica (001) was determined according to ISO 14729:2001. Bacterial biofilm of these 2 strains was then grown on contact lens storage 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 :
Cleadew MPDS performed well against planktonic forms of the bacterial strains tested; no viable organisms were recovered after 4 hours. Biotrue MPDS showed less than 3.0 log colony forming units (CFU) reduction of A. xylosoxidans 001 (-1.9 log CFU; p<0.05) and E. meningoseptica 001 (-0.6 log CFU; p<0.05) after 4 hours. Cleadew MPDS was effective in removing bacterial biofilm from contact lens storage cases of both the test strains. All 3 storage case hygiene procedures reduced the biofilm of both strains by more than 3.0 log CFU (p<0.001). Air-drying rather than recapping the contact lens storage cases wet following disinfection was better for removing A. xylosoxidans 001 (-1.2 log CFU; p<0.5) and E. meningoseptica 001 (-1.9 log CFU; p<0.05) biofilm.
Conclusions :
This study has shown that Cleadew MPDS is effective against planktonic and biofilm forms of emerging ocular pathogens. The results also highlight the importance of air-drying on lens case hygiene.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.