Primary HIV-1 drug resistance and polymorphic patterns among injecting drug users (IDUs) in Chennai, Southern India.

BACKGROUND AND OBJECTIVE: India has 1.1 million injecting drug users (IDUs) with an HIV prevalence rate as high as 64%. Drug resistance screening before therapy is beneficial to the individual. Here, we have studied primary drug resistance among IDUs in Chennai. METHODS: Specimens (n = 55) collected between March 2005 and April 2006 were subjected to genotyping assay. The mutations for the drug resistance were interpreted using the Stanford HIV Drug Resistance Database. RESULTS: M41LM (1.8%), K65KN (1.8%), and G73GS (2.7%) were found to be associated with low-level resistance to zidovudine (ZDV), stavudine (d4T), abacavir (ABC), didanosine (ddI), emtricitabine (FTC), tenofovir (TDF), and saquinavir (SQV) in each specimen. The rate of polymorphisms is significantly different from universally established subtype ''C''-specific polymorphisms (P < .0001). CONCLUSION: The presence of drug resistance mutations, though minimal, is alarming as it could spread easily between IDUs and from them to their sexual partners. The genetic variation is of importance in vaccine design.

Use of an HIV-1 reverse-transcriptase enzyme-activity assay to measure HIV-1 viral load as a potential alternative to nucleic acid-based assay for monitoring antiretroviral therapy in resource-limited settings.

An inexpensive and technically less-demanding methodology to quantify HIV-1 viral load would be of great value for resource-limited settings, where the nucleic-acid amplification technique (NAAT) is impractical and/or resource-prohibitive. In this study, an HIV-1 reverse-transcriptase enzyme-activity assay (ExaVir Load assay, version 1) was compared with the gold standard RT-PCR assay, Roche HIV-1 Amplicor Monitor, version 1.5. A total of 121 plasma specimens were used for the evaluation. ExaVir Load had a sensitivity of 97 % and a specificity of 71 % in identifying specimens with <400 copies ml(-1) in the Roche RT-PCR assay as being less than the detection limit of the assay (5500 copies ml(-1)). The mean difference (95 % limits of agreement) between Roche RT-PCR and ExaVir Load was -0.23 (-1.59 to 1.13) log(10)(copies ml(-1)) by Bland-Altman analysis. Significant negative correlations were seen between CD4(+) T-cell counts and the ExaVir Load assay (r=-0.32, P<0.05), and between CD4(+) T-cell counts and the Roche RT-PCR (r=-0.38, P<0.01). The present study with HIV-1 showed a strong correlation between the ExaVir Load assay and the RT-PCR assay. Hence, the ExaVir Load assay could be considered for use in resource-limited settings as an alternative viral-load assay to the standard NAAT-based assay after further evaluation with prospective specimens.

Evaluation and diagnostic usefulness of domestic and imported enzyme-linked immunosorbent assays for detection of human immunodeficiency virus type 1 antibody in India.

Diagnosis of human immunodeficiency virus (HIV) infection is important for patient management and prevention of new infections. The number of test kits available for the detection of HIV antibodies is unprecedented. In order to identify appropriate test kits, we evaluated a variety of commercial kits manufactured abroad as well as in India. The plasma and serum specimens (n=264) were collected from individuals attending the Voluntary Counseling and Testing Centre at the YRG Centre for AIDS and Education. The specimens were used to evaluate six commercially available HIV test kits: Enzaids HIV 1+2, HIV-CheX, Murex HIV-1.2.0, Genscreen HIV 1/2 version 2, Vironostika HIV Uni-Form II Ag/Ab, and CombAids RS Advantage. High sensitivities and specificities (>or=99%) were observed for the Enzaids, Murex, Vironostika, and CombAids assays. HIV-CheX showed the highest number of false-positive and false-negative results. The Genscreen test also gave many false positives. The study indicated that the Enzaids, Murex, and Vironostika enzyme-linked immunosorbent assay kits and the CombAids RS Advantage rapid assay could be used to achieve acceptable results for the detection of HIV antibodies. A combination of two tests is recommended to optimize the efficiency of HIV antibody testing algorithms, especially when evaluation with an HIV Western blot confirmatory test is not possible.