The effect of storage time and temperature on the recovery of pathogen DNA from polytetrafluorethylene (PTFE) was investigated. PTFE impression membranes were inoculated with Pseudomonas aeruginosa, Herpes Simplex Virus-1 (HSV-1) or Acanthamoeba and stored at -70 °C, -20 °C, +4 °C or +35 °C. PCR was performed on days 0, 1, 2, 3, 7 and months 1, 3 and 10 post-inoculation. We found no reduction in the DNA recovery of any of the studied microorganisms for the first 3 days of storage up to +35 °C. For HSV-1 and P. aeruginosa, storage for 3 months at +35 °C was associated with a significant reduction in DNA recovery (P<0.001), but not at +4 °C, -20 °C or -70 °C for 1 month for P. aeruginosa and for 10 months for HSV-1. Acanthamoeba DNA recovery was not affected by any storage parameters (P=0.203). These results will inform the investigation of microbial keratitis where access to microbiological testing is not readily available.
Keywords: Acanthamoeba; HSV-1; P. aeruginosa; corneal impression membrane; microbial keratitis.