Abstract
Purpose:
Contact lenses are a significant risk factor for microbial keratitis. Contact lens storage hygiene may be a significant factor in this risk. The microbial environment on contact lenses and cases has not been re-investigated using deep DNA sequencing. We applied Biome Representational in Silico Karyotyping (BRiSK) and 16s rDNA deep DNA sequencing techniques to samples collected from the conjunctiva, soft contact lenses, and contact lens cases of nine subjects.
Methods:
Conjunctiva, buccal mucosa and skin were swabbed using forensic DNA recovery swabs. Contact lenses and the interior of cases were soaked in phosphate buffered saline and sampled. DNA was purified and analyzed by BRiSK and 16s rDNA. 33 bp DNA sequence tags from BRiSK and 16s rDNA gene sequences were compared to a comprehensive database for species identification.
Results:
16s rDNA was applied to 85 samples from 9 subjects (including left and right contact lens cases, left and right contact lenses, upper and lower conjunctiva from both eyes, buccal, and skin samples). BRiSK was applied to 41 samples from 5 subjects (contact lens cases, contacts, and conjunctival samples). High quality DNA was found in 26 samples from BRiSK. Both 16s and BRiSK demonstrated organisms found in common and in high proportions in conjunctiva, contact lenses, and cases, which include Propionibacterim, coagulase negative Staphylococcus, and Pseudomonas genera. Remarkably, BRiSK revealed multiple sequence tags corresponding to seven serotypes of human papillomavirus (HPV) in the contact lens cases from three of five subjects, although HPV was not recovered from lens or conjunctival samples.
Conclusions:
Deep DNA sequencing of samples from conjunctiva, contact lenses, and contact lens cases demonstrate a rich microbial environment in contact lens cases and a general correlation of genera between sample locations. HPV sequences were recovered from numerous contact lens cases suggesting that cases are a potential source of viral infection.