ABSTRACT
Objective To clarify the genetic diversity of HIV-1 strains currently circulating in Shanghai and establish the molecular epidemiological database of HIV-1 infection.Methods The samples from 114 newly diagnosed HIV-l-infected individuals between June 2004 and June 2005 were investigated.HIV-1 pol gene(protease 1-99 aa and reverse transcriptase 1-252 aa) from plasma sam- ples were amplified by RT-PCR,sequenced and phylogenetieally analyzed.Protease inhibitors(PRIs) and reverse transcriptase inhibitors (RTIs) resistance-associated mutations in protease (PR) and re- verse transcriptase(RT) regions were analyzed.Results (1)Epidemiological survey showed the exist ence of different modes of transmission of HIV-1 including sexual contacts 51(44.74%),intravenous drug users 43 (37.72%),contaminated blood/blood products transfusion 3(2.63%) and unknown in- fection 17(14.91%);(2)Phylogenetic analysis revealed that 9 of the analyzed sequences were identi- fied as subtype B(7.89%),15 as subtype B'(13.16%),1 as subtype C(0.88%),1 as subtype G (0.88%),38 as CRF01 AE(33.33%),46 as CRF07 BC(40.35%) and4 asCRF08 BC(3.51%); (3)Analysis of drug-resistance associated mutation showed that 21 of 114 (18.42%) persons infected with drug-resistant HIV-1,among which major mutations in PR and RT regions accounted for 2.63 (3/114) and 17.54% (20/114),respectively.The frequencies of major mutation in PR region were M46I(66.67%),M46L(33.33%) and in RT region were M41L(7.69%),A62V (7.69%),T69S (7.69%),V75I/L(15.38%),K103R(25.00%),V118I(23.08%),V179D/E/T(33.33%),G190R (8.33%),L210K/M/X(38.46%),227L/I(16.67%),M230R(8.33%),P236R(8.33%).Conclusions The results revealed the current presence of multiple HIV-1 subtypes and recombinants strains infec- ting residents and migrants living in Shanghai.The broad diversity of HIV-1 has been introduced into Shanghai mainly through drug injection and heterosexual contacts.This study also revealed that HIV-1 strains infecting these newly diagnosed treatment-naive persons have acquired major mutations in both PR gene and RT gene of HIV-1.