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Drug resistance mutations and sub-type circulation in newly diagnosed HIVinfected subjects

Abstract number: O237

Parisi S., Boldrin C., Cruciani M., Scaggiante R., Bosco O., Manfrin V., Ferretto R., Panese S., Rossi M.C., Dal Bello F., Cecchetto M.G., Andreis S., Palù G.

Objectives: to evaluate circulation trends of drug resistance mutations (DRM) and viral sub-types (ST) among subjects recently diagnosed as HIV infected (pts), over a five years period in a region with a wide availability of therapeutic options.

Methods: Plasma from 832 pts diagnosed from July 2004 to December 2008 in the Veneto region (Italy) were studied. The protease (PR) and the reverse transcriptase (RT) were sequenced and analysed for the presence of major DRMs, for drug susceptibility profile (Stanford database) and ST. Potential low level resistance were not considered. A c-square test for linear trends was applied.

Results: The main results were as follows: in four different periods, 2004–5, 2006, 2007 and 2008, were recruited 168, 166, 244 and 254 pts respectively; mean cd4 percentage (±SD) were 20.9 (±11), 21 (±10.6), 22 (±10.5), 20.9 (±10.8); B-ST pts (% of total) were 138 (82.2), 123 (74.1), 173 (70.9) and 183 (72); pts with DRMs in B-ST (% of total B-pts) were 30 (21.7), 25 (20.3), 20 (11.6) and 22 (12); pts with DRMs in Non-B-ST (%) were 7 (23.3), 6 (14), 5 (7) and 3 (4.2). A significant increase of non-B-ST (p = 0.021) and a significant decrease in DRMs (p < 0.001) were observed. CRF02_AG was the prevalent non-B ST (44%). 35.3% of non-B ST pts were italians. Among B-ST, DRMs predicted a reduced susceptibility to one drug class in 23, 17, 15 and 14 cases in the different periods; to two drug classes in 4, 6, 5 and 8; to three classes in 3, 2, 0 and 0. In non-B-ST, a reduced susceptibility to one drug class was found in 6, 6, 4 and 0 cases; to two drug classes in 1, 0, 0 and 2; to three drug classes in 0, 0, 1 and 1, respectively. Among pts with one or two classes of resistance, a decrease of percentage of Protease Inhibitors related DRMs, and a persistence of Non Nucleoside RT Inhibitors involving DRMs, mainly 103N and 190A, were observed.

Conclusions: An increase of non-B strains was observed, only partially related to a modification of the ethnic composition of the cohort. The observed decrease of the DRMs prevalence and of the multidrug resistant strains in both B and non-B groups is probably related to the reduction of viraemic and failing pts spreading resistant viruses, and to the increase of subjects unaware of their infection and transmitting wild-type viruses. The substantial circulation of NNRTI-related DRMs has important implications on the selection of the first-line HAART.

Session Details

Date: 16/05/2009
Time: 00:00-00:00
Session name: 19th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Helsinki, Finland, 16 - 19 May 2009
Presentation type:
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