title: Prevalence of drug-resistant HIV-1 variants in untreated individuals in Europe: implications for clinical management.
abstract: BACKGROUND
  Infection with drug-resistant human immunodeficiency virus type 1 (HIV-1) can impair the response to combination therapy. Widespread transmission of drug-resistant variants has the disturbing potential of limiting future therapy options and affecting the efficacy of postexposure prophylaxis.
  
  
  METHODS
  We determined the baseline rate of drug resistance in 2208 therapy-naive patients recently and chronically infected with HIV-1 from 19 European countries during 1996-2002.
  
  
  RESULTS
  In Europe, 1 of 10 antiretroviral-naive patients carried viruses with > or = 1 drug-resistance mutation. Recently infected patients harbored resistant variants more often than did chronically infected patients (13.5% vs. 8.7%; P=.006). Non-B viruses (30%) less frequently carried resistance mutations than did subtype B viruses (4.8% vs. 12.9%; P<.01). Baseline resistance increased over time in newly diagnosed cases of non-B infection: from 2.0% (1/49) in 1996-1998 to 8.2% (16/194) in 2000-2001.
  
  
  CONCLUSIONS
  Drug-resistant variants are frequently present in both recently and chronically infected therapy-naive patients. Drug-resistant variants are most commonly seen in patients infected with subtype B virus, probably because of longer exposure of these viruses to drugs. However, an increase in baseline resistance in non-B viruses is observed. These data argue for testing all drug-naive patients and are of relevance when guidelines for management of postexposure prophylaxis and first-line therapy are updated.
authors.affiliation: Eijkman Winkler Institute, Department of Virology, University Medical Center Utrecht, The Netherlands.
authors.forename: Annemarie M J
authors.initials: AM
authors.lastname: Wensing
authors.forename: David A
authors.initials: DA
authors.lastname: van de Vijver
authors.forename: Gioacchino
authors.initials: G
authors.lastname: Angarano
authors.forename: Birgitta
authors.initials: B
authors.lastname: Asjö
authors.forename: Claudia
authors.initials: C
authors.lastname: Balotta
authors.forename: Enzo
authors.initials: E
authors.lastname: Boeri
authors.forename: Ricardo
authors.initials: R
authors.lastname: Camacho
authors.forename: Maire-Laure
authors.initials: ML
authors.lastname: Chaix
authors.forename: Dominique
authors.initials: D
authors.lastname: Costagliola
authors.forename: Andrea
authors.initials: A
authors.lastname: De Luca
authors.forename: Inge
authors.initials: I
authors.lastname: Derdelinckx
authors.forename: Zehava
authors.initials: Z
authors.lastname: Grossman
authors.forename: Osamah
authors.initials: O
authors.lastname: Hamouda
authors.forename: Angelos
authors.initials: A
authors.lastname: Hatzakis
authors.forename: Robert
authors.initials: R
authors.lastname: Hemmer
authors.forename: Andy
authors.initials: A
authors.lastname: Hoepelman
authors.forename: Andrzej
authors.initials: A
authors.lastname: Horban
authors.forename: Klaus
authors.initials: K
authors.lastname: Korn
authors.forename: Claudia
authors.initials: C
authors.lastname: Kücherer
authors.forename: Thomas
authors.initials: T
authors.lastname: Leitner
authors.forename: Clive
authors.initials: C
authors.lastname: Loveday
authors.forename: Eilidh
authors.initials: E
authors.lastname: MacRae
authors.forename: Irina
authors.initials: I
authors.lastname: Maljkovic
authors.forename: Carmen
authors.initials: C
authors.lastname: de Mendoza
authors.forename: Laurence
authors.initials: L
authors.lastname: Meyer
authors.forename: Claus
authors.initials: C
authors.lastname: Nielsen
authors.forename: Eline L
authors.initials: EL
authors.lastname: Op de Coul
authors.forename: Vidar
authors.initials: V
authors.lastname: Ormaasen
authors.forename: Dimitris
authors.initials: D
authors.lastname: Paraskevis
authors.forename: Luc
authors.initials: L
authors.lastname: Perrin
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Puchhammer-Stöckl
authors.forename: Lidia
authors.initials: L
authors.lastname: Ruiz
authors.forename: Mika
authors.initials: M
authors.lastname: Salminen
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Schmit
authors.forename: Francois
authors.initials: F
authors.lastname: Schneider
authors.forename: Rob
authors.initials: R
authors.lastname: Schuurman
authors.forename: Vincent
authors.initials: V
authors.lastname: Soriano
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Stanczak
authors.forename: Maja
authors.initials: M
authors.lastname: Stanojevic
authors.forename: Anne-Mieke
authors.initials: AM
authors.lastname: Vandamme
authors.forename: Kristel
authors.initials: K
authors.lastname: Van Laethem
authors.forename: Michela
authors.initials: M
authors.lastname: Violin
authors.forename: Karin
authors.initials: K
authors.lastname: Wilbe
authors.forename: Sabine
authors.initials: S
authors.lastname: Yerly
authors.forename: Maurizio
authors.initials: M
authors.lastname: Zazzi
authors.forename: Charles A
authors.initials: CA
authors.lastname: Boucher
mesh_terms: D000328:Adult; D019943:Amino Acid Substitution; D024882:Drug Resistance, Viral / Q000235:genetics*; D005060:Europe; D005260:Female; D015658:HIV Infections / Q000188:drug therapy / Q000821:virology*; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D008297:Male; D020125:Mutation, Missense