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.