Molecular epidemiology of human immunodeficiency virus type 1 in Guangdong province of southern China

Abstract

Background: Although the outbreak of human immunodeficiency virus type 1 (HIV-1) in Guangdong has been documented for more than a decade, the molecular characteristics of such a regional HIV-1 epidemic remained unknown.

Methodology/principal findings: By sequencing of HIV-1 pol/env genes and phylogenetic analysis, we performed a molecular epidemiologic study in a representative subset (n = 200) of the 508 HIV-1-seropositive individuals followed up at the center for HIV/AIDS care and treatment of Guangzhou Hospital of Infectious Diseases. Of 157 samples (54.1% heterosexual acquired adults, 20.4% needle-sharing drug users, 5.7% receivers of blood transfusion, 1.3% men who have sex with men, and 18.5% remained unknown) with successful sequencing for both pol and env genes, 105 (66.9%) HIV-1 subtype CRF01_AE and 24 (15.3%) CRF07_BC, 9 (5.7%) B', 5 (3.2%) CRF08_BC, 5 (3.2%) B, 1 (0.6%) C, 3 (1.9%) CRF02_AG, and 5 (3.2%) inter-region recombinants were identified within pol/env sequences. Thirteen (8.3%) samples (3 naïves, 6 and 5 received with antiretroviral treatment [ART] 1-21 weeks and ≥24 weeks respectively) showed mutations conferring resistance to nucleoside/nonnucleoside reverse transcriptase inhibitors or protease inhibitors. Among 63 ART-naïve patients, 3 (4.8%) showed single or multiple drug resistant mutations. Phylogenetic analysis showed 8 small clusters (2-3 sequences/cluster) with only 17 (10.8%) sequences involved.

Conclusion/significance: This study confirms that sexual transmission with dominant CRF01_AE strain is a major risk for current HIV-1 outbreak in the Guangdong's general population. The transmission with drug-resistant variants is starting to emerge in this region.

Figure 1. Characteristics of HIV-1 infected individuals in Guangzhou Hospital of Infectious Diseases in 2009.

The geographical distribution of 462 patients (Guangdong’s residents) was represented by different levels of gray and the parentheses showed cases of patients enrolled in HIV-1 pol/env sequence analysis versus overall patients in this city/county (A). Comparison of characteristics between patients enrolled into the sequence analysis and overall patients, including their age, occupation, risk factors and treatments (B).

Figure 2. Phylogenetic tree (maximum likelihood) and genotypes of HIV-1 in Guangdong’s patients.

Continual lines connected the inter-subtype recombination sequences of pol (left) and env (right) trees from the same patient.