HIV-1 multi-dideoxynucleoside resistance mutation (Q151M): prevalence, associated resistance mutations and response to antiretroviral salvage treatment

The prevalence and clinical implications of the Q151M multidrug-resistance mutation gene (mut) to antiretroviral drugs in the HIV reverse transcriptas e (RT) gene have not yet been fully explained. In the present study three o ut of 350 (0.85%) of HIV-infected patients who underwent a drug-resistance genotyping assay because of therapeutic failure showed the Q151M mut. All t hese patients had been previously treated with zidovudine in association wi th didanosine. One such patient failed to respond to all salvage regimens t ried and was shown to harbour some of the characteristic mut associated wit h Q151M (77L and 116Y). Another two patients partially responded to salvage regimens, both virologically and immunologically, and harboured the M184V mut in the RT gene. The prevalence of Q151M mut in our group was less (0.85 %) than in other studies, which ranged from 2 to 19%. The M184V mut seemed to confer some viro-immunological benefit when associated with the Q151M mu tation, compared with the latter alone.