title: Single- and multidrug resistance mutations to reverse transcriptase and protease inhibitors: human immunodeficiency virus type 1-infected patients from two geographical areas in Spain. Spanish Groups for Antiretroviral Resistance Studies.
abstract: OBJECTIVE
  To describe the prevalence of genotypic resistance mutations, including single and multidrug resistance (MDR) to reverse transcriptase (RT) and protease (PR) inhibitors in treated and untreated patients from two geographical areas in Spain (Madrid and Galicia).
  
  
  METHODS
  Resistance mutations to RT inhibitors were studied by line probe assay (LiPA) or by automated sequencing in 468 patients (Madrid, 268; Galicia, 200), and resistance mutations to PR inhibitors were studied by automated sequencing in 295 patients (Madrid, 85; Galicia, 210).
  
  
  RESULTS
  The proportion of resistance mutations in treated and untreated patients results were higher by the LiPA method than by sequencing. By sequencing, we detected resistance mutations to nucleoside analogue RT (NRT) inhibitors and NRT inhibitors plus nonnucleoside RT (NNRT) inhibitors in 35.4% and 17.2% of treated patients, respectively. We also detected MDR to zidovudine plus lamivudine in 13.9% of treated patients from Galicia, in 1.7% from Madrid (p < 0.001), and in 1.5% of untreated patients from Galicia. Also, we detected MDR to NRT inhibitors in 3.8% and to NNRT inhibitors in 9.1%. We found resistance mutations to PR inhibitors in 38.1% of treated patients and in 0.9% of untreated patients.
  
  
  CONCLUSIONS
  These findings reinforce the usefulness of testing for resistance mutations in some cases to evaluate their prevalence in a given population and in the follow-up of treated patients.
authors.affiliation: Centro Nacional de Biología Fundamental, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Pérez-Alvarez
authors.forename: M L
authors.initials: ML
authors.lastname: Villahermosa
authors.forename: M T
authors.initials: MT
authors.lastname: Cuevas
authors.forename: E
authors.initials: E
authors.lastname: Delgado
authors.forename: N
authors.initials: N
authors.lastname: Manjón
authors.forename: E
authors.initials: E
authors.lastname: Vázquez de Parga
authors.forename: L
authors.initials: L
authors.lastname: Medrano
authors.forename: G
authors.initials: G
authors.lastname: Contreras
authors.forename: M M
authors.initials: MM
authors.lastname: Thomson
authors.forename: C
authors.initials: C
authors.lastname: Colomo
authors.forename: J A
authors.initials: JA
authors.lastname: Taboada
authors.forename: R
authors.initials: R
authors.lastname: Nájera
mesh_terms: D015331:Cohort Studies; D004279:DNA, Viral / Q000032:analysis; D004352:Drug Resistance, Microbial; D018432:Drug Resistance, Multiple; D004359:Drug Therapy, Combination; D015658:HIV Infections / Q000188:drug therapy / Q000453:epidemiology / Q000821:virology*; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics*; D006801:Humans; D019259:Lamivudine / Q000494:pharmacology / Q000627:therapeutic use; D009154:Mutation; D017354:Point Mutation; D011480:Protease Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D011533:Proviruses; D012367:RNA, Viral / Q000235:genetics; D018894:Reverse Transcriptase Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D013030:Spain / Q000453:epidemiology; D015215:Zidovudine / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: D004279:DNA, Viral; D011480:Protease Inhibitors; D012367:RNA, Viral; D018894:Reverse Transcriptase Inhibitors; D019259:Lamivudine; D015215:Zidovudine