HIV drug resistance in the United Kingdom - Update
Resistance among drug-experienced individuals provides indirect evidence about the contribution of drug resistance to virological failure, and information critical for modelling the future spread of resistant virus. As described more in more detail in an earlier CDR weekly report (1), findings are based on genotypic test results reported to the UK HIV Drug Resistance Database, which aims to collect all tests conducted as part of routine clinical care, including samples sent to the Health Protection Agency's (HPA) Antiviral Susceptibility Reference Unit.
At the study's inception in 2001, the first task undertaken was the collection of the results of all retrospective tests (limited resistance testing began in 1996). Participating virology laboratories now provide data on an annual basis.
* In reverse transcriptase: (i) any mutation at G190 or T215 (ii) T69N.
Resistance is defined as one or more major mutations listed in the International AIDS Society-USA 2003 guidelines (2), plus additional mutations* agreed by the virologists who are members of the UK Collaborative Group on HIV Drug Resistance.
Mutations are classified according to the class of drug to which they confer resistance:
(i) the nucleoside/nucleotide reverse transcriptase inhibitors (NRTI)
(ii) non-nucleoside reverse transcriptase inhibitors (nNRTI)
(iii) protease inhibitors (PI).
Although a fourth class of drug (fusions inhibitors) is now available, as yet these are rarely prescribed and the part of the HIV genome relevant to resistance to this class is not routinely sequenced.
Results
The analysis includes tests reported up to May 2004, although data for 2003 are incomplete. Children aged under 16 years are excluded, as most will have been infected via mother-to-infant transmission and are thus likely to have different resistance characteristics compared with adults infected by other routes.
Estimates of the prevalence of resistance among drug naive individuals are based on 2410 tests (1 test per individual). Resistance to any class, ( ie , NRTI, nNRTI, or PI) has increased steadily over calendar time. In 2002/2003, the prevalence of any class, NRTI, nNRTI, and PI resistance was 24%, 15%, 8%, and 10% respectively (table1, figure 1). Resistance across two or more drug classes was rare; of the 422 samples that harboured any mutations, 340 (81%) showed resistance to a single drug class only………………….. CONTINUES……..HEALTH PROTECTION AGENCY, UK
HIV rezistenþei la medicament în Regatul Unit al Marii Britanii - Update - HIV drug resistance in the United Kingdom - Update - articole medicale engleza - startsanatate