title: Transmission of resistant HIV type 1 variants and epidemiological chains in Italian newly diagnosed individuals.
abstract: Transmission of HIV-1 and drug resistance continue to occur at a considerable level in Italy, influenced mainly by changes in modality of infection. However, the long period of infectivity makes difficult the interpretation of epidemiological networks, based on epidemiological data only. We studied 510 naive HIV-1-infected individuals, of whom 400 (78.4%) were newly diagnosed patients with an unknown duration of infection (NDs), with the aim of identifying sexual epidemiological networks and transmitted drug resistance (TDR) over a 7-year period. Clusters were identified by Bayesian methods for 412 patients with B subtype; 145 individuals (35.2%) clustered in 34 distinct clades. Within epidemiological networks males were 93.1% (n=135); the same proportion of patients has been infected by the sexual route; 62.1% (n=90) were men having sex with men (MSM) of whom 67.8% (n=61) were NDs. Among heterosexuals (n=44), males were predominant (79.5%, n=35) and 77.3% (n=34) were NDs. TDR in clusters was 11.7 % (n=17), of whom 76.5% (n=13) was found in MSM. TDR was predominantly associated with NRTI resistance in individuals with chronic infection (n=11). A high prevalence of epidemiological networks has been found in the metropolitan area of Milan, indicating a high frequency of transmission events. The cluster analysis of networks suggested that the source of new infections was mainly represented by males and MSM who have long lasting HIV-1 infection. Notably, the prevalence of resistance-conferring mutations was higher in chronically infected patients, carrying mainly resistance to thymidine analogs, the backbone of first antiretroviral (ARV) generation. Intervention strategies of public health are needed to limit HIV-1 transmission and the associated TDR.
authors.affiliation: Department of Clinical Sciences L. Sacco Hospital, Section of Infectious Diseases and Immunopathology, University of Milan, Milan, Italy. alessia.lai@unimi.it
authors.forename: Alessia
authors.initials: A
authors.lastname: Lai
authors.forename: Michela
authors.initials: M
authors.lastname: Violin
authors.forename: Erika
authors.initials: E
authors.lastname: Ebranati
authors.forename: Marco
authors.initials: M
authors.lastname: Franzetti
authors.forename: Valeria
authors.initials: V
authors.lastname: Micheli
authors.forename: Maria Rita
authors.initials: MR
authors.lastname: Gismondo
authors.forename: Amedeo
authors.initials: A
authors.lastname: Capetti
authors.forename: Paola
authors.initials: P
authors.lastname: Meraviglia
authors.forename: Francesco Roberto
authors.initials: FR
authors.lastname: Simonetti
authors.forename: Giorgio
authors.initials: G
authors.lastname: Bozzi
authors.forename: Masimo
authors.initials: M
authors.lastname: Ciccozzi
authors.forename: Massimo
authors.initials: M
authors.lastname: Galli
authors.forename: Gianguglielmo
authors.initials: G
authors.lastname: Zehender
authors.forename: Claudia
authors.initials: C
authors.lastname: Balotta
mesh_terms: D000328:Adult; D000368:Aged; D019380:Anti-HIV Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001499:Bayes Theorem; D024882:Drug Resistance, Viral / Q000235:genetics*; D005260:Female; D015658:HIV Infections / Q000453:epidemiology / Q000635:transmission* / Q000821:virology; D015497:HIV-1 / Q000235:genetics / Q000472:pathogenicity; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010802:Phylogeny; D015995:Prevalence; D012725:Sexual Behavior; D011795:Surveys and Questionnaires; D013936:Thymidine / Q000031:analogs & derivatives; D055815:Young Adult
chemical_list: D019380:Anti-HIV Agents; D013936:Thymidine