Purpose: This study assessed microbiome adherent to contact lenses and defined the bacterial communities associated with use of lens care solutions.
Methods: Among 84 lenses screened for adherent ocular surface bacterial microbiome using 16S rRNA molecular amplification, 63 (75%) generated bacterial-specific amplicons processed using the Ion Torrent Personal Genome Machine workflow. Data were stratified by solution use (peroxide vs. polyhexamethylene biguanide [PHMB]-preserved multipurpose solution [MPS]). Diversity of lens-adherent microbiome was characterized using Shannon diversity index and richness index. Data were analyzed using principal components analysis and Kruskal-Wallis tests.
Results: We identified 19 phyla and 167 genera of bacteria adherent to the lenses. Proteobacteria was the most abundant phyla, followed by Firmicutes and Actinobacteria. The most abundant bacterial genera (>1% abundance) were Ralstonia, Enterococcus, Streptococcus, Halomonas, Corynebacterium, Staphylococcus, Acinetobacter, Shewanella, Rhodococcus, and Cobetia. Sixteen of 20 lenses (80%) negative for bacterial DNA were worn by participants using peroxide solutions while only 4 (20%) were MPS-treated lenses (P=0.004). Genera diversity of lens-adherent microbiome showed a significant increase in MPS-treated lenses compared with peroxide (P=0.038). Abundance of Corynebacterium, Haemophilus, and Streptococcus were increased 4.3-, 12.3-, and 2.7-fold, respectively, in the MPS group compared with peroxide (P=0.014, 0.006, 0.047, respectively).
Conclusions: Commensal, environmental, and pathogenic bacteria known to be present in the conjunctival microbiome can be detected on worn contact lenses. Although most contact lenses worn by asymptomatic wearers harbor bacterial DNA, compared with peroxide, lenses stored in a PHMB-preserved MPS have more quantifiable, abundant, and diverse bacterial communities adherent to them.