16th International HIV Drug Resistance Workshop 12-16 June 2007, Barbados

HIV-1 TRANSMISSION DYNAMICS IN RECENT SEROCONVERTERS: RELATIONSHIP WITH TRANSMISSION OF DRUG RESISTANCE AND VIRAL DIVERSITY

Antivir Ther. 2007; 12:S43 (abstract no. 36)

P Recordon-Pinson¹, O Peuchant¹, S Capdepont¹, V Lavignolle², D Neau^2,3, P Morlat³, JL Pellegrin³, R Thiébaut², F Dabis², H Fleury¹, B Masquelier ¹ and the ANRS CO3 Aquitaine Cohort
¹Laboratoire de Virologie CHU de Bordeaux et EA2968, Université Victor Segalen, Bordeaux, France; ²INSERM U593 and EO 338, Université Victor Segalen, Bordeaux, France; ³Département des Maladies Infectieuses, CHU de Bordeaux, France

BACKGROUND: HIV-1 has been shown to be frequently transmitted by acutely infected patients. We wished to investigate the relationship between the dynamics of HIV-1 transmission within recently infected patients and HIV-1 variability and transmission of antiretroviral drug resistance.

METHODS: We included patients from the Aquitaine Cohort with a date of seroconversion between 1996 and 2005, with a plasma sample obtained less than 18 months after seroconversion and prior starting antiretroviral therapy. Reverse transcriptase (RT) and protease sequences were determined by direct population sequencing from plasma samples. Genotypic resistance was interpreted with the ANRS 2006 algorithm. Phylogenetic analysis (neighbour joining and maximum likelihood methods) of RT and protease sequences determined the HIV-1 subtype and the interrelationship between the sequences.

RESULTS: RT and protease sequences could be determined for 229 recent seroconverters. The sequences clustered with clade B in 192 (84%) patients and with non-B subtypes in 36 (16%) patients. The prevalence of resistance to at least one drug was 15.7%, and did not differ between B and non-B isolates (18.2% versus 8.3%; P=0.22). The clusters of transmission were only evidenced within B sequences, of which 66 (34.4%) segregated into 18 clusters. The median cluster size was 2.5 (range 2–14). Drug-resistant isolates were retrieved in only three clusters. The prevalence of resistance in clustering viruses was however 10/66 (15.2%).

CONCLUSION: The dynamics of HIV-1 transmission in this cohort in south-western France was clearly shown to be different in patients infected with B and non-B HIV-1 isolates. The high frequency of forward transmission events in subtype B-infected patients can lead to an overtransmission of drug resistant isolates with particular patterns and pleads for earlier antiretroviral therapy in recently infected patients and for increasing prevention efforts in developed countries.

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2007-06-12
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