The genetic resistance to nucleoside inhibitors of the reverse transcriptase (RT) of human immunodeficiency virus I (HIV-1) isolates in the Czech Republic was examined by a line probe assay (LiPA) and nucleotide sequencing. The results of LiPA analysis of 294 blood specimens obtained from 156 patients revealed a high incidence of mutations in the RT gene related to resistance to various drugs (67.3%) in various combinations. Mutations in RT gene (M41L, K70R and T215Y/F) conferring the resistance to zidovudine (ZDV) were most frequent (62.6%), that (M184V) responsible for the resistance to lamivudine (3TC) was less frequent (33.7%), while those linked to the resistance to dideoxyinosine (ddl) and dideoxyinosine together with dideoxycytidine (ddl/ddC) were rather rare (6.5% and 5.1%, respectively). LiPA gave a high rate of uninterpretable results due to codon hybridization failure, especially in HIV-1 isolates of non-B subtype. Thirty-two specimens were analyzed also by direct sequencing of a part of RT gene. The results obtained by LiPA and the sequencing were highly concordant for codons successfully analyzed by both methods, but the sequencing provided information also about the codons that could not be analyzed by LiPA. A high prevalence of resistant strains in the Czech Republic and their heterogeneity justifies a regular HIV-1 resistance testing. LiPA turned out as a fast, powerful and most reliable tool for such a purpose. However, due to an increasing diversity of HIV-1 strains circulating in the Czech Republic, LiPA cannot replace the nucleotide sequence analysis.

National Reference Laboratory on AIDS National Institute of Public Health Prague Czech Republic