Genotypic analyi of cytomegaloviru retiniti poorly reponive to intravenou ganciclovir but reponive to the ganciclovir implant

Purpoe To determine whether cytomegaloviru (CMV) retiniti that reponded poorly to intravenou ganciclovir therapy but reponded to the ganciclovir implant wa caued by viru with reitance mutation in the viral UL97 and UL54 gene. Deign Retropective chart review and laboratory-baed experimental tudy. Method Region of the CMV UL97 and UL54 were amplified from the vitreou and analyzed for reitant mutation by a combination of DNA equencing and retriction digetion. Vitreou from patient with AID and retinal infection other than CMV retiniti erved a negative control. Reult We amplified all target region of UL97 DNA and mot target region of UL54 DNA from eight eye with CMV retiniti. In one eye we found a ganciclovir reitance mutation at bae 1781 of the UL97 gene, predicting an alanine to valine mutation at codon 594. In a econd eye we found a ganciclovir reitance mutation at bae 2960 of the UL54 gene, predicting an alanine to glycine mutation at codon 987. In two additional eye, both from patient with bilateral retiniti, we found UL54 mutation that are likely to confer reitance to ganciclovir but have not been previouly decribed. In both of thee patient the UL54 genotype differed between the two dieaed eye. Concluion Failure to control CMV retiniti with intravenou ganciclovir doe not necearily imply infection with a viru having a known mutation that confer drug reitance. The ganciclovir implant can be an effective therapy for CMV retiniti caued by viru with certain UL97 and UL54 reitance mutation. Cytomegaloviru UL54 genotype can differ between eye in patient with bilateral retiniti.