title: Herpes simplex virus resistant to acyclovir. A study in a tertiary care center.
abstract: OBJECTIVE
  To determine the sensitivity of herpes simplex virus isolates to acyclovir and the importance of resistant isolates in hospitalized patients.
  
  
  METHODS
  Retrospective incidence cohort study.
  
  
  METHODS
  All herpes simplex virus isolates cultured over 1 year from patients followed at a tertiary care center.
  
  
  METHODS
  Consecutive herpes simplex virus isolates were collected from 207 patients, including immunocompetent patients, patients with malignancy, neonates, bone marrow and organ transplant recipients, and patients seropositive for human immunodeficiency virus.
  
  
  RESULTS
  A rapid nucleic acid hybridization method was used to assess susceptibility to acyclovir. Acyclovir-resistant herpes simplex viruses were recovered from 7 of 148 immunocompromised patients (4.7%) but from none of 59 immunocompetent hosts. Clinical disease was found in all 7 patients with resistant herpes simplex virus and was more severe in pediatric patients. All resistant isolates were from acyclovir-treated patients and had absent or altered thymidine kinase activity by plaque autoradiography.
  
  
  CONCLUSIONS
  Herpes simplex virus resistant to acyclovir arises relatively frequently in immunocompromised patients and may cause serious disease. Rapid detection of resistance permits antiviral therapy to be individualized. Antiviral susceptibility testing to monitor viral resistance should be encouraged, especially in tertiary care settings.
authors.affiliation: University of Minnesota Health Sciences Center, Minneapolis.
authors.forename: J A
authors.initials: JA
authors.lastname: Englund
authors.forename: M E
authors.initials: ME
authors.lastname: Zimmerman
authors.forename: E M
authors.initials: EM
authors.lastname: Swierkosz
authors.forename: J L
authors.initials: JL
authors.lastname: Goodman
authors.forename: D R
authors.initials: DR
authors.lastname: Scholl
authors.forename: H H
authors.initials: HH
authors.lastname: Balfour
mesh_terms: D000212:Acyclovir / Q000494:pharmacology*; D000328:Adult; D016026:Bone Marrow Transplantation / Q000276:immunology; D004352:Drug Resistance, Microbial; D005260:Female; D015658:HIV Infections / Q000276:immunology; D006785:Hospitals, University; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D008910:Minnesota; D009369:Neoplasms / Q000276:immunology; D009693:Nucleic Acid Hybridization; D018139:Simplexvirus / Q000187:drug effects* / Q000302:isolation & purification; D014181:Transplantation Immunology
chemical_list: D000212:Acyclovir