The study of dual HIV infection prevalence in Russia

Objective. To develop and validate the method of dual HIV infection detection based on the results of Sanger sequencing and to evaluate of dual HIV infection frequency in Russia. Materials and methods. We carried out the sequencing of HIV-1 pol gene fragment in model samples of dual HIV infection, the calculation of degeneracy bases index (DB-index), and the index of synonymity (SM-index) and determination of their threshold values for dual HIV infection detection. We analyzed nucleotide sequences of the pol gene fragment in HIV-1 samples (n = 1561) taken from Russian patients. Results. The threshold values of 34 for the DB-index and 0.05 for the SM-index allow detecting effectively the dual HIV infection using reverse transcriptase (RT) and protease-reverse transcriptase (PR-RT) fragments of the pol gene correspondingly. At total 21 (1.35%) dual HIV-infected samples (18 of which were collected in 2014 and later) were revealed in the collection studied; 12 of them were obtained from patients residing in the Central Federal District. An inverse correlation between the likelihood of dual HIV infection detecting and the duration of the patient's infection was found. In total, 11 out of 21 samples with dual HIV infection had mutations associated with drug resistance; 7 of them (33.3%) had substitutions that were not associated with natural polymorphism of HIV-1. Conclusion. The problem of dual HIV infection in Russia is actual and requires further study. Key words: HIV, dual HIV infection, drug resistance, nucleotide sequence, DB-index, SM-index, PR-RT region