[Contribution of the laboratory in case of resistance to acyclovir of herpes simplex and varicella zoster virus].
Herpes simplex virus (HSV) and varicella zoster virus (VZV) are susceptible to acyclovir which inhibits viral replication through two viral enzymes, thymidine kinase (TK) and DNA polymerase. Resistance may occur, it is a rare phenomenon among immunocompetent patients but resistance is more frequent and may be associated with serious complications among immunocompromised patients. Virological survey of these at risk patients is needed to detect resistant virus as soon as possible through phenotypic tests performed on virus isolated on cell cultures. Resistant virus may also be genetically characterised by detection of mutations within TK and DNA polymerase genes. Pharmacological parameters also have to be taken into consideration and a determination of acyclovir blood concentration should be performed in case of unexplained therapeutic failure. Improvement of immune system, when possible, may resolve these infections. Alternative treatments using drugs such as foscarnet or cidofovir which have a different mechanism of action compared to acyclovir, are recommended but these molecules are often more toxic than acyclovir.
Morfin
F
F
Laboratoire de virologie des Hospices civils de Lyon, Domaine Rockefeller, 8 avenue Rockefeller, 69373 Lyon cedex 08. fmorfin@rockefeller.univ-lyon1.fr
Frobert
E
E
Thouvenot
D
D
D000212:Acyclovir / Q000494:pharmacology*; D000998:Antiviral Agents / Q000494:pharmacology*; D002644:Chickenpox / Q000188:drug therapy; D024882:Drug Resistance, Viral; D006561:Herpes Simplex / Q000188:drug therapy; D006562:Herpes Zoster / Q000188:drug therapy; D014645:Herpesvirus 3, Human / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D009154:Mutation; D010641:Phenotype; D018139:Simplexvirus / Q000187:drug effects* / Q000235:genetics
D000998:Antiviral Agents; D000212:Acyclovir