title: Herpes simplex virus drug-resistance: new mutations and insights.
abstract: OBJECTIVE
  Acyclovir (ACV) is the first-line treatment for the management of herpes simplex virus 1 (HSV-1) and 2 (HSV-2) diseases. Long-term administration of the drug for the treatment of chronic infections in the immunocompromised host can lead to the development of ACV-resistance. This review provides an update of the mutations linked to drug-resistance and issues to be considered in the management of HSV infections refractory to antiviral therapy.
  
  
  RESULTS
  Recent data have shown that HSV drug-resistance should be taken into account not only in immunocompromised individuals but also in immunocompetent persons when HSV infections involve 'immune-privileged sites'. Thus, drug-resistance typing is recommended in cases of ACV unresponsive herpetic keratitis and herpes simplex encephalitis. Several issues regarding HSV drug-resistance were highlighted by recent studies. Phenotypic and genotypic antiviral resistance may vary not only from different compartments but also over time, highlighting the importance of characterizing longitudinal HSV isolates from all sites. Combination therapy should be considered when viruses with distinct phenotype/genotype are identified at one or at distinct body sites.
  
  
  CONCLUSIONS
  Surveillance of HSV drug-resistance is highly recommended in immunocompromised patients and in immunocompetent individuals with infections implicating 'immune-privileged sites' to rationally adapt antiviral treatment.
authors.affiliation: Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, KU Leuven, Leuven, Belgium.
authors.forename: Graciela
authors.initials: G
authors.lastname: Andrei
authors.forename: Robert
authors.initials: R
authors.lastname: Snoeck
mesh_terms: D000212:Acyclovir / Q000494:pharmacology / Q000627:therapeutic use*; D000998:Antiviral Agents / Q000494:pharmacology / Q000627:therapeutic use*; D024882:Drug Resistance, Viral / Q000235:genetics*; D006561:Herpes Simplex / Q000175:diagnosis / Q000188:drug therapy* / Q000821:virology; D006801:Humans; D007121:Immunocompetence; D016867:Immunocompromised Host
chemical_list: D000998:Antiviral Agents; D000212:Acyclovir