Molecular typing of the local HIV-1 epidemic in Serbia.

Worldwide HIV-1 pandemic is becoming increasingly complex, with growing heterogeneity of subtypes and recombinant viruses. Previous studies have documented HIV-1 subtype B as the predominant one in Serbia, with limited presence and genetic diversity of non B subtypes. In recent years, MSM transmission has become the most frequently reported risk for HIV infection among newly diagnosed patients in Serbia, but very little is known of the network structure and dynamics of viral transmission in this and other risk groups. To gain insight about the HIV-1 subtypes distribution pattern as well as characteristics of HIV-1 transmission clusters in Serbia, we analyzed the genetic diversity of the pol gene segment in 221 HIV-1-infected patients sampled during 2002-2011. Subtype B was found to still be the most prevalent one in Serbia, accounting for over 90% of samples, while greater diversity of other subtypes was found than previously reported, including subtypes G, C, A, F, CRF01 and CRF02. In total, 41.3% of analyzed subtype B sequences were found associated in transmission clusters/network, that are highly related with MSM transmission route.