Moderate prevalence of transmitted drug resistance and interiorization of HIV type 1 subtype C in the inland North State of Tocantins, Brazil.

The diverse Brazilian AIDS epidemic has reached small cities and scant molecular information is available about the epidemic in Northern Brazil, where the incidence is growing. This study describes transmitted drug resistance and subtypes in the protease (PR) and reverse transcriptase (RT) regions among naive patients recruited in Palmas, the capital of Tocantins State, a newly built city in Northern Brazil. PR/RT regions were retrotranscribed from plasma HIV-1 RNA and 52 were sequenced after direct nested PCR. HIV-1 subtypes were assigned by phylogenetic analysis. Transmitted drug resistance was analyzed by the Calibrated Population Resistance tool Stanford Surveillance Drug Resistance Mutation. Most patients included (59.6%) were males, the median age was 30 years and were mainly referred because of heterosexual or homosexual unprotected sex. One male patient was from the Karajás indigenous tribe. The prevalence of transmitted resistance was 11.5% (CI 95%, 4.4-23.4%): nonnucleoside RT inhibitor mutations (n=3), nucleoside RT inhibitor mutations (n=2), and protease inhibitor mutations (n=1). Dual or triple class resistance was not observed. HIV-1 subtype B(PR)/B(RT) represented 78.8%, 5.8% were subtype C(PR)/C(RT), and 1.9% were subtype F1(PR)/F1(RT). Recombinant viruses represented 13.5% (07/52): B(PR)/F1(RT) (n=1), B(PR)/BF1(RT) (n=4), and C(PR)/CF1(RT) (n=2). This study about the AIDS epidemic in the recently founded city of Palmas/Tocantins in inland Northern Brazil shows moderate levels of transmitted drug resistance and the circulation of diverse recombinant viruses. This pattern is similar to what has been described in major metropolitan cities, suggesting the influence of imported cases from the south/southeast. Moreover these results indicate that patients from this setting should be monitored regarding transmitted drug resistance mutations.