[Molecular epidemiology and transmission of HIV in Tianjin, 2015]

To understand the characteristics on the diversity of HIV subtypes and related transmission in Tianjin.

A total of 77 newly diagnosed ART-naïve HIV infectors in 2015 were screened by CD4(+) T cell counts ≥200 cells/μl. Viral RNAs were extracted from plasma samples. Reverse transcription PCR and nested PCR were used to analyze the amplification of pol and env gene fragments, sequencing, and related bioinformatics information.

46.03% (29/63), 30.16% (19/63), 11.11% (7/63), 4.76% (3/63) and 7.94% (5/63) of the individuals were infected under HIV subtypes CRF01_AE, CRF07_BC, B, CRF55_01B and URFs, with sexual transmission as the major mode of infection. CRF01_AE and CRF07_BC strains were predominant in both MSM and HST populations. The patterns of subtype distribution did not show statistical differences other than subtype B and CRF55_01B strain among HSTs. The proportion of CRFs increased significantly to 88.89%. 8 new second-generation recombinant forms were identified the first time, including 3 CRF55_01B, 2 AE/BC, 1 AE/B and 1AE/B/C among MSMs and 1 AE/BC among HSTs. 5.3% of the NNRTI L100I HIV infectors transmitted the drug-resistant-mutation strain. 3 linkages related to HIV transmission were confirmed through phylogenetic analysis with Bootstrap ≥98% of pol and ≥80% of env.

The increasing complexity of HIV had been noticed in Tianjin, including the prevalence and transmission of second-generation recombinant and drug-resistant strains through different routes of transmission and in different regions.