Distinct resistance mutation and polymorphism acquisition in HIV-1 protease of subtypes B and F1 from children and adult patients under virological failure.

The goal of this work was to compare the differences between human immunodeficiency virus type 1 (HIV-1) of B and F1 subtypes in the acquisition of major and minor protease inhibitor (PI)-associated resistance mutations and of other polymorphisms at the protease (PR) gene, through a cross sectional study. PR sequences from subtypes B and F1 isolates matched according to PI exposure time from Brazilian patients were included in this study. Sequences were separated in four groups: 24 and 90 from children and 141 and 99 from adults infected with isolates of subtypes F1 and B, respectively.

Differential drug resistance acquisition in HIV-1 of subtypes B and C.

Background: Subtype C is the most prevalent HIV-1 subtype in the world, mainly in countries with the highest HIV prevalence. However, few studies have evaluated the impact of antiretroviral therapy on this subtype. In southern Brazil, the first developing country to offer free and universal treatment, subtypes B and C co-circulate with equal prevalence, allowing for an extensive evaluation of this issue.

Epidemiologic and evolutionary trends of HIV-1 CRF31_BC-related strains in southern Brazil.

Background: To evaluate the impact of HIV-1 CRF31_BC in the southern Brazilian HIV epidemic.

Methods: Blood plasma from 284 patients was collected from July 2002 to January 2003 at 2 reference HIV/AIDS centers in southern Brazil. Viral protease and reverse transcriptase (RT) genomic regions were amplified by RT polymerase chain reaction, sequenced, and subtyped.

Characterization of a new circulating recombinant form comprising HIV-1 subtypes C and B in southern Brazil.

Objective: To identify a new circulating recombinant form (CRF) of HIV-1 comprising two circulating subtypes in the southern region in Brazil, subtypes B and C.

Methods: A total of 152 HIV-positive patients followed at two hospitals in southern Brazil had their viral pol genes isolated by reverse transcriptase-polymerase chain reaction (PCR) from plasma. PCR products were sequenced and phylogenetically analysed using HIV-1 subtype reference sequences.