title: Frequency of acyclovir-resistant herpes simplex viruses isolated from the general immunocompetent population and patients with acquired immunodeficiency syndrome.
abstract: BACKGROUND
  Herpes simplex virus (HSV) infections are usually chronically recurrent in the normal population and represent a significant cause of morbidity in immunocompromised patients. Acyclovir (ACV) is widely used for the treatment and prophylaxis of HSV infections. The emergence of ACV-resistant strains has been frequently reported as a result of long-term ACV therapy.
  
  
  OBJECTIVE
  Despite the widespread use of ACV, there are no data available in our area on the frequency of ACV-resistant HSVs. The purpose of this study was to evaluate the susceptibility of HSV isolated from normal subjects and patients with acquired immunodeficiency syndrome (AIDS) to ACV.
  
  
  METHODS
  HSVs were isolated from the orofacial region of normal individuals and patients with AIDS. The susceptibility of isolated HSV strains to various concentrations of ACV was determined by plaque reduction assay. The sensitivity of the viral strains was expressed as IC(50) (the concentration of drug reducing the viral plaque by 50%).
  
  
  RESULTS
  One hundred and thirty-three isolates from 102 normal subjects and 31 patients with AIDS were tested. One HSV-1 isolate from normal individuals had intermediate susceptibility. Two ACV-resistant isolates (one HSV-1 and one HSV-2), with IC(50) > or = 2 to < or = 3 microg/mL, and one highly resistant HSV-2 isolate, with IC(50) > or = 5 microg/mL, were detected in patients with AIDS.
  
  
  CONCLUSIONS
  Our data show that the prevalence of ACV-resistant strains is very low in the general immunocompetent population; however, in patients with AIDS, the prevalence of ACV-resistant strains is remarkable (P = 0.001). Alternative antiherpetic agents should be employed to control and reduce the emergence of ACV-resistant strains in patients with AIDS.
authors.affiliation: Professor Alborzi Clinical Microbiology Research Center and Department of Internal Medicine, Shiraz University of Medical Sciences, Shiraz, Iran. ziyaeyanm@sums.ac.ir
authors.forename: Mazyar
authors.initials: M
authors.lastname: Ziyaeyan
authors.forename: Abdolvahab
authors.initials: A
authors.lastname: Alborzi
authors.forename: Aziz
authors.initials: A
authors.lastname: Japoni
authors.forename: Mohammad
authors.initials: M
authors.lastname: Kadivar
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Davarpanah
authors.forename: Bahman
authors.initials: B
authors.lastname: Pourabbas
authors.forename: Amin
authors.initials: A
authors.lastname: Abassian
mesh_terms: D017088:AIDS-Related Opportunistic Infections / Q000188:drug therapy / Q000821:virology*; D000163:Acquired Immunodeficiency Syndrome / Q000821:virology; D000212:Acyclovir / Q000494:pharmacology* / Q000627:therapeutic use; D000293:Adolescent; D000328:Adult; D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology* / Q000627:therapeutic use; D002648:Child; D002522:Chlorocebus aethiops; D024882:Drug Resistance, Viral; D005260:Female; D006561:Herpes Simplex / Q000188:drug therapy / Q000821:virology*; D018259:Herpesvirus 1, Human / Q000187:drug effects* / Q000302:isolation & purification; D018258:Herpesvirus 2, Human / Q000187:drug effects* / Q000302:isolation & purification; D006801:Humans; D007121:Immunocompetence; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D014709:Vero Cells
chemical_list: D000998:Antiviral Agents; D000212:Acyclovir