Prevalence of HIV-1 drug resistance in treated patients: a French nationwide study.
BACKGROUND
Surveillance of HIV-1 drug resistance in antiretroviral-treated patients is important from the public health perspective of the spread of resistance and to evaluate the proportion of patients for whom new drugs are needed.


METHODS
Patients were consecutively included in 28 centers in France and 1 center in Switzerland if they had a viral load measurement performed in June 2004, with a result >or=1,000 copies/mL. Reverse transcriptase, protease, and gp41 genes were sequenced, and resistance mutations were reported as listed on the Web site ( www.iasusa.org). The genotypic resistance results were interpreted by the Agence Nationale de Recherches sur le SIDA et les Hepatites Virales (ANRS) and Stanford algorithms.


RESULTS
The 498 patients included had been exposed to 9 (interquartile ratio [IQR]: 6 to 12) antiretroviral drugs. Patients' viruses harbored 4 nucleoside reverse transcriptase inhibitor (IQR: 1 to 6) and 4 protease inhibitor (PI; IQR: 2 to 8) resistance mutations, whereas 44% had at least 1 nonnucleoside reverse transcriptase inhibitor resistance mutation. The frequency of resistance to at least 1 drug was 88% with the ANRS algorithm and 83% with the Stanford algorithm. The frequencies of complete resistance to 1, 2, and 3 classes of drugs were 37%, 15%, and 4%, respectively, with the ANRS algorithm and 27%, 23%, and 24%, respectively, with the Stanford algorithm. The most important differences between algorithms were for PIs. Using the ANRS algorithm and extrapolation on the whole French database, 19% of all treated patients could contribute to the spread of resistance and 4% had complete resistance to 2 classes of antiretroviral drugs.


CONCLUSIONS
The observed patterns of resistance are linked to a long-lasting history of antiretroviral therapy. The frequency of multiresistance can vary according to the interpretation systems.
Costagliola
Dominique
D
INSERM, Unité Mixte de Recherche (UMR) S 720, Université Pierre et Marie Curie-Paris 6, Paris, France.
Descamps
Diane
D
Assoumou
Lambert
L
Morand-Joubert
Laurence
L
Marcelin
Anne-Geneviève
AG
Brodard
Véronique
V
Delaugerre
Constance
C
Mackiewicz
Vincent
V
Ruffault
Annick
A
Izopet
Jacques
J
Plantier
Jean-Christophe
JC
Tamalet
Catherine
C
Yerly
Sabine
S
Saidi
Souhaha
S
Brun-Vezinet
Françoise
F
Masquelier
Bernard
B
D000328:Adult; D019380:Anti-HIV Agents / Q000494:pharmacology*; D024921:Drug Resistance, Multiple, Viral; D005260:Female; D005602:France / Q000453:epidemiology; D015658:HIV Infections / Q000188:drug therapy* / Q000453:epidemiology / Q000821:virology*; D015497:HIV-1 / Q000187:drug effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence
D019380:Anti-HIV Agents