Research article

Molecular and phylogenetic analysis of HIV-1 variants circulating in Italy

Luigi Buonaguro¹ , Annacarmen Petrizzo¹ , Maria Tagliamonte¹ , Francesca Vitone² , Maria Carla Re^2,3 , Elisabetta Pilotti⁴ , Claudio Casoli⁵ , Costanza Sbreglia⁶ , Oreste Perrella⁶ , Maria Lina Tornesello¹ and Franco M Buonaguro¹

¹  Laboratory of Molecular Biology and Viral Oncogenesis & AIDS Reference Center, Istituto Nazionale Tumori "Fondazione Giovanni Pascale", Naples – Italy

²  Section of Microbiology of the Department of Hematology, Oncologic Science, Anatomical Pathology and Microbiology, University of Bologna, Bologna – Italy

³  Interuniversity Consortium, National Institute Biostructure and Biosystem (INBB), Rome – Italy

⁴  Department of Clinical Medicine, Nephrology, and Health Sciences, University of Parma, Parma – Italy

⁵  Department of Clinical Sciences, Infectious Diseases Unit 'L. Sacco', University of Milano – Italy

⁶  VII Division of Infectious Diseases, Cotugno Hospital, Naples – Italy

author email corresponding author email

Infectious Agents and Cancer 2008, 3:13doi:10.1186/1750-9378-3-13

Published:	10 October 2008

Abstract

Objective

The continuous identification of HIV-1 non-B subtypes and recombinant forms in Italy indicates the need of constant molecular epidemiology survey of genetic forms circulating and transmitted in the resident population.

Methods

The distribution of HIV-1 subtypes has been evaluated in 25 seropositive individuals residing in Italy, most of whom were infected through a sexual route during the 1995–2005 period. Each sample has been characterized by detailed molecular and phylogenetic analyses.

Results

18 of the 25 samples were positive at HIV-1 PCR amplification. Three samples showed a nucleotide divergence compatible with a non-B subtype classification. The phylogenetic analysis, performed on both HIV-1 env and gag regions, confirms the molecular sub-typing prediction, given that 1 sample falls into the C subtype and 2 into the G subtype. The B subtype isolates show high levels of intra-subtype nucleotide divergence, compatible with a long-lasting epidemic and a progressive HIV-1 molecular diversification.

Conclusion

The Italian HIV-1 epidemic is still mostly attributable to the B subtype, regardless the transmission route, which shows an increasing nucleotide heterogeneity. Heterosexual transmission and the interracial blending, however, are slowly introducing novel HIV-1 subtypes. Therefore, a molecular monitoring is needed to follow the constant evolution of the HIV-1 epidemic.