Antiviral susceptibility of cytomegakovirus isolated

ABSTRACT

Two wild-types clinical cytomegalovirus [CMV] isolates were plaque purified and the individual plaque variants were then randomly picked and passed 3-5 times in human foreskin fibroblast [MRHF] to increase viral titer and test for susceptibility to the antiviral ganciclovir [DHPG]. Different susceptibility pattern to DHPG has been identified among the individual plaques tested with an inhibitory concentration 50 [ID50] ranged from 0.08-14.2 muM. Also, a fully sensitive [DHPG ID50 <5 muM], intermediate resistant [DHPG ID50 between 6-10 muM] and resistant [DHPG ID50 >10 muM] plaque purified viral isolates were further tested for susceptibility to other antiviral agents [foscarnet and HPMPC]. All the tested individual strains [DHPG sensitive and resistant] remained susceptible to foscarnet and HPMPC. It may be concluded that within any resistant population of CMV to DHPG, there was a marked heterogenicity with some subsets of the population remaining susceptible to the drug and others exhibiting considerable level of resistance. DHPC resistant CMV isolates remained susceptible to the other antiviral drugs [foscarnet and HPMPC meaning that therapy with these two antiviral agents would still be available