Objective: To survey the level and patterns of reverse transcriptase-based drug resistance and subtype distribution among antiretroviral-treated HIV-infected patients receiving only reverse transcriptase inhibitors in Iran.
Methods: A total of 25 samples of antiretroviral therapy experienced patients with no history of using protease inhibitors were collected. After RNA extraction, reverse transcriptase-nested PCR was performed. The final products were sequenced and then analysed for drug-resistant mutations and subtypes.
Results: No drug resistant mutations were observed among the 25 subjects. The results showed the following subtypes among patients:CRF 35_AD (88%), CRF 28_BF (8%), and CRF 29_BF (4%).
Conclusions: A significant increase in drug resistance has been noted in recently-infected patients worldwide. Subtype distributions are needed to perform properly-designed surveillance studies to continuously monitor rates and patterns of transmitted drug resistance and subtypes to help guide therapeutic approaches and limit transmission of these variants.

Objective: To survey the level and patterns of reverse transcriptase-based drug resistance and subtype distribution among antiretroviral-treated HIV-infected patients receiving only reverse transcriptase inhibitors in Iran. Methods: A total of 25 samples of antiretroviral therapy experienced patients with no history of using protease inhibitors were collected. After RNA extraction, reverse transcriptase-nested PCR was performed. The final products were sequenced and then analysed for drug-resistant mutations and subtypes. Results: No drug resistant mutations were observed among the 25 subjects. The results showed the following subtypes among patients: CRF 35_AD (88%), CRF 28_BF (8%), and CRF 29_BF (4%). Conclusions: A significant increase in drug resistance has been noted in recently-infected patients worldwide. Subtype distributions are needed to perform properly-designed surveillance studies to continuously monitor rates and patterns of transmitted drug resistance and subtypes to help guide therapeutic approaches and limit transmission of these variants.