Abstract
Purpose :
Acanthamoeba keratitis, is considered one of the most serious ocular pathologies. Cleaning and disinfection of contact lenses is essential to prevent possible corneal related infections. The purpose of this study was to analyze the efficacy of several commercial contact lens disinfection systems against Acanthamoeba (AC) using quantitative PCR (qPCR) to detect AC RNA.
Methods :
Three different contact lens (CL) materials (Plafufocon D (RGP); Comfilcon A (Hy) and Ocufilcon D (Si-Hy)) and four contact lens disinfection (Hydrogen Peroxide (HP), sodium hypochlorite (SH), Povidone (Po) and multipurpose solution (MS)) combining or not with a CL cleaner (isopropyl alcohol (IA)) were studied. The lenses were contaminated with AC (105 amoeba/ml) and incubated for 24h at 30 C. The CLs (n=8) were divided into different cleaning treatment groups after a tap water rinse (Positive and negative control, contact lens disinfection system with or without CL cleaner before). After the cleaning treatment, the AC was extracted with freeze saline solution and stored with RLT solution at -80 C. HSP70 and TPBF genes were analysed to detect the AC presence using quantitative PCR (qPCR), all reactions in duplicate. Data are presented as mean and SD of cycle threshold (Ct) obtained in the PCR (quantitative data) and % of positives (presence of AC) or negatives (absence of AC). P value<0.05 was considered statistically significant.
Results :
The Ct threshold for hsp70 gen was 30.21 (lower values were considered positive values). Only MS disinfection showed 56% of positives in RGP (Ct: 29.93±2.20) lenses and 100% for both hydrogel materials (Ct: 26.26±2.51 for Hy and 25.42±2.14 for Si-Hy). When MS combined with IA, 12,5% of positives for Si-Hy (Ct: 33.61±2.84) and 100% of negatives for Hy (Ct: 35.11±1.62) and RGP (Ct: 34.95±2.13) were found (p<0.05). Po showed 12.5% and 38% and a lack of positives in Si-Hy, Hy and RGP, respectively. However, PO combined with IA was 100% effective against AC. For all materials, HP and SH, combined or not with IA, were effective against AC, except the HP without IA for Hy lenses.
Conclusions :
The use of qPCRs based on the detection of AC mRNA as an alternative to DNA-based PCRs provides more information on the status of the AC. In addition, all contact lenses disinfection systems used showed to have any effect on AC in any CL material. The most effective solutions were those based on HP and SA.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.