Study On HIV-1 Drug-resistant Mutation Status In Fujian Province And Subtype Analysis Of HIV-1 Strains Circulated In HIV-1 Infected MSM

CD~4+ T cell count and viral load (VL) testing were conducted for human immunodeficiency virus type 1 (HIV-1) infected patients who were recveiving antiretroviral therapy (ART) in Fujian province from 2008 to 2010. Samples with VL upper than 1000 copies/ml were further using to conduct genotypic drug-resisitance testing. The whole protease(PR) and partial reverse transcriptase (RT) genes of HIV-1 were amplified using reverse transcription polymerase chain reaction (RT-PCR ) and then sequenced. The sequences of those amplified fragment were edited using the software Contig Express, and then submitted to the website http://hivdb.stanford.edu/ to analyze their drug resistance status. Refer to national surveillance strategy for transmitted drug-resistant HIV-1, part of MSM (men who have sex with men) HIV-1 infected persons who were diagnosed in 2007 to 2010 in Fujian province and didn't receive ART previously was involved in this study to analysis the primary drug-resistance status. In addition, the fragments of p17-24 gene in gag structural region and C2-V5 or gp41 gene in env gene region were also amplified and sequenced for subtype analysis to illustrate the major HIV-1 strains circulated MSM in Fujian province.For the patients having ART, most of them have achieved significant effectiveness including suppression of virus replication and recovery of immune system to some extend. The suppression rate of viral load showed in this study were 88.8% in 2008,84.4% in 2009 and 90.3% in 2010. Regarding to CD~4+ T cell count, the patients'immune system recovered gradually after ART initiation, but failed to reconstruct because of drug -resistant HIV-1 strains emerged. Results of drug-resistance genotypic testing showed that many mutations for non-nucleoside reverse transcriptase inhibitors (NNRTIs) and nucleoside reverse transcriptase inhibitors (NRTIs) existed in 26 sequences and 25 of them caused low to high level of resistance to NNRTIs and NRTIs. There were several major or minor resistance mutants for protease inhibitors (PIs) observed in 4 sequences. The overal resistant rate is up to 69.4%(25/36).However, the genotypic drug-resistance analysis of MSM HIV-1 infected patients showed a significant lower mutaion rate compared with patients receiving ART. 5 of 50 sequences occured mutations for PIs, only one was interpreted as medium lever resistant to NFV. 1 of 10 sequences occurring mutations for NNRTIs and NRTIs was interpreted as potential low lever resistance to relevant drugs. The results revealed good consistence to our previous studies of Fujian province.Acoording to subtype analysis, tow subtypes (B and C) and three kinds of circulating reconbinant forms (CRFs, CRF01_AE,CRF08_BC and CRF12_BF ) existed in patients receiving ART. The dominant strain circulating in these patients is CRF01_AE. Subtypes of strains circulating in MSM HIV-1 infected patients in Fujian province include B, CRF01_AE, CRF07_BC and CRF08_BC. 30 of 50 strains were classified as CRF01_AE. The phylogenetic trees constructed with sequences of MSM HIV-1 infected patients showed similar structure of pol, gag and env genes. The analysis of genetic variations of diferrent genes and subtypes showed env gene with higer divergency than pol and gag genes. Genetic variation of Subtype B was significantly greater than other subtypes which may indicate that subtype B circulated in this group eariler than other subtypes. By comparing with general population in Fujian province in previous studies we found the genetic distances among strains circulating in MSM is relatively shorter which means the strains may recently imported to MSM in Fujian province which reminded us to enhance monitoring HIV and regard for rapid spread of HIV in this population.