Abstract
Purpose: :
Adenoviral infections of the ocular surface are frequent and potentially severe. Adenoviral serotypes 8, 19 and 37 are most frequently found in epidemic conjunctivitis and keratitis. Microbiological diagnostic tests need currently several days (cytopathogenic tests) or did not prouve their efficacy in ophthalmology. The goal of this study was to evaluate a new method of detection and semi–quantification of Adenoviruses in samples obtained by conjunctival scraping.
Methods: :
Magnapure System was used to obtain nucleic acids for amplification. ABI PRISM was employed for Real Time PCR . Oligonucleotides and probes were choosen to match 8, 19, and 37 serotypes.Amplification program included 50 C° for 50 minutes then 95C° for 10 minutes followed by 42 cycles of 15 seconds at 95C° and 60 seconds at 60C°.
Results: :
a)The sensitivity of this method has been estimated at 8x10–5 Plaque Forming Unit. b) In 20 patients suffering of bilateral adenoviral keratoconjunctivitis (microbiologically proven by viral culture) the Real Time PCR was positive in 100% of the cases. c) No cross reactions with human genome or infective pathogens were observed.
Conclusions: :
Real time PCR allowed to detect the equivalent of 0.1 copies of adenoviral DNA in conjunctival samples of patients affected by viral conjunctivitis. After DNA extraction Real Time PCR results were obtained faster than 2hours30 time. The good quality of the sample abtained by scraping was confirmed by human DNA ( found in all tested samples).
Keywords: adenovirus • conjunctiva • keratitis