755   Prevalence of Genotypic Drug Resistance among French Patients Infected during the Year 1999.

M. L. Chaix*¹, M. Harzic², B. Masquelier³, I. Pellegrin³, L. Meyer⁴, D. Costagliola⁵, C. Rouzioux¹, F. Brun-Vezinet⁶, Ac11 Resistance Group Cohort, and Primo and Primoferon Study Groups.
¹Hop. Necker, Paris;²Hop. Versailles;³Hop. Pellegrin, Bordeaux;⁴INSERM U292, Kremlin-Bicêtre;⁵SC4 INSERM; and⁶Hop. Bichat, Paris, France.

Background:The objective of this study was to assess the prevalence of genotypic antiretroviral resistance among patients who presented with HIV primary infection during the year 1999.

Methods:108 patients were enrolled in three interlaboratory studies: the ANRS AC11 Resistance group (n = 57), the Primo-Infection Cohort study group (n = 40) and the Primoferon study group (n = 11). The route of infection was homo- or bisexual contact for 71% of the patients and heterosexual contact for 29%. The sex ratio M/F was 4.7. Plasma were collected before any treatment initiation and tested for genotypic resistance analysis by sequencing reverse transcriptase and protease genes with an in-house method on an ABI 377 A automated sequencer (Perkin-Elmer) or with the TrueGene HIV-1 genotyping kit (VGI).

Results:Mutations to at least one class of antiretrovirals were present in 11 samples (10.1%, [95% CI: 5.2— 17.5]). The distribution of the resistance mutations was as follows: to NRTIs in 7/108 (6.5%, [95% CI: 2.6— 12.9]; 2 to 3TC (M184V), 2 to ZDV (T215Y) and 3 to ZDV + 3TC (M184V + T215Y or T215F)) and to NNRTIs in 4/108 (3.7%, [95% CI: 1.0—9.2]; 2 × K103N, 2 × Y181C). Primary resistance mutations to protease inhibitors were detected in 3/105 (2.8%, [95% CI: 5.8—7.9]; L90M, V82A, I84V). Primary mutations to 1 or 2 classes of antiretrovirals were present in samples 9 and 1, respectively. A multi-drug resistance pattern was observed in 1 sample (K103N, Q151M, M184V, M46I, V82A), conferring a resistance to the 3 classes of ARV drugs.

Conclusions:This large national study establishes the prevalence of resistance mutations among patients recently infected in France. Because of the constant evolution in the prescriptions of antiretroviral treatments, such epidemiological surveys must continue.