title: Incidence of zidovudine-resistant human immunodeficiency virus isolated from patients before, during, and after therapy.
abstract: The zidovudine sensitivity of 372 isolates of human immunodeficiency virus (HIV) obtained from 237 patients before, during, and after treatment with zidovudine was examined. Virus resistant to > 0.5 micrograms/mL (1.87 microM) zidovudine was isolated from most patients (93%) after 36 months of therapy. Zidovudine-sensitive virus was isolated from 5 of 15 patients who had ended antiretroviral therapy but had previously shed resistant virus. The emergence of sensitive virus after end of therapy appeared to be influenced by both the duration of treatment and the time off drug. Patients with resistant virus tended to have low CD4 cell counts and HIV antigenemia at the commencement of therapy, suggesting that these two factors are important in the development of drug resistance.
authors.affiliation: Virology Department, Fairfield Hospital, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Land
authors.forename: C
authors.initials: C
authors.lastname: McGavin
authors.forename: R
authors.initials: R
authors.lastname: Lucas
authors.forename: C
authors.initials: C
authors.lastname: Birch
mesh_terms: D015704:CD4 Antigens / Q000032:analysis; D004352:Drug Resistance, Microbial; D005260:Female; D006678:HIV / Q000187:drug effects* / Q000302:isolation & purification / Q000502:physiology; D015488:HIV Antigens / Q000097:blood; D015658:HIV Infections / Q000188:drug therapy* / Q000276:immunology / Q000382:microbiology; D006467:Hemophilia A / Q000150:complications; D006716:Homosexuality; D006801:Humans; D008297:Male; D015819:Substance Abuse, Intravenous / Q000150:complications; D016176:T-Lymphocyte Subsets / Q000276:immunology; D014779:Virus Replication / Q000187:drug effects; D015215:Zidovudine / Q000494:pharmacology* / Q000627:therapeutic use*
chemical_list: D015704:CD4 Antigens; D015488:HIV Antigens; D015215:Zidovudine