Drug resistant mutations detected by genotypic drug resistance testing in patients failing therapy in clade C HIV-1 infected individuals from India

Purpose: There has been an increase in the number of individuals administered antiretroviral therapy (ART) in India but treatment outcome is hampered by increasing development of drug resistance. Previous reports from India have shown M184V as the commonest mutation in treated individuals. However, there is no evidence for any protease mutations in these reports. This study was done to observe the common/unique mutational patterns observed in reverse transcriptase (RT) and protease (Pr) genes of clade C HIV-1 strains from individuals showing treatment failure in India.
Materials and Methods: The assay was done by sequencing the Pr and RT genes of the HIV-1 strains from 18 individuals failing ART. Analysis was carried out using Stanford HIV drug resistance database (SHDB). The sequences were also submitted to the calibrated population resistance tool of SHDB and Rega HIV-1 sub typing tool. Phylogenetic analysis and quality control were performed with Mega 4.
Results: Among the 20 strains, 19 showed resistance to both nucleoside reverse transcriptase inhibitors (NRTIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs), one strain to NNRTIs and five strains showed protease inhibitors (PI) resistance and 3-class resistance. The most common mutation conferring NRTI resistance was M184V (90%) while K103N (45%) was the most common mutation conferring NNRTI resistance. The M46I mutation was seen in 20% of the Pr sequences.
Conclusion: Resistance testing to check the prevalence of drug resistance mutations that arise following failure of the first line regimen to establish guidelines for second line regimens in India is a must. Studies are needed to confirm if mutation patterns that arise among clade C following failure of ART are the same as for clade B strains.