Prevalence of antiretroviral drug resistance among naive Spanish patients infected with HIV

INTRODUCTION. Genotypic resistance was tested to investigate changes in the rates of resistance to antiretroviral drugs in non-treated patients in Spain. MATERIAL AND METHOD. A total of 209 HIV-infected patients from different autonomous communities in Spain without prior antiretroviral (AR) drug treatment were studied from 1997 to 2001. Regions of the HIV pol gene coding for protease (PR) and retrotranscriptase (RT) were sequenced in plasma samples by RT PCR amplification and automated PCR sequencing. RESULTS. At least one primary RT or PR mutation was detected in 14 patients (6.7%); 11 of them were associated with resistance to RT inhibitors (5.3%) and 3 to PR inhibitors (1.4%). The changes in the resistance rate between March 1997-February 1999 and March 1999-February 2001 were as follows: resistance mutations were detected in 3 of the 111 patients studied in the first period, and in 10 of 98 patients in the second period (2.7% versus 10.2%, P = 0.025). The infection time was less than three months in 1.5% of cases, less than 1 year in 13.4%, more than 1 year in 45.9% and unknown in 39.2%. CONCLUSION. The rate of primary resistance in naive patients is low in Spain, although there may be a trend toward an increase. The rising prevalence of resistance is a cause for concern.