engleski

Identification of HIV-1 transmission clusters in Croatia, 2014-2017: evidence for the forward spread of HIV-1 resistant variants

Purpose: Phylogenetic analysis is a useful tool for identification of HIV-1 transmission clusters and analysis of biological characteristics of individual clusters. The aim of the study was to determine and characterize transmission networks that are responsible for the forward spread of HIV-1 infection and resistant variants in Croatia. Method: We analyzed 403(95.9%) of 428 newly HIV-diagnosed persons who entered clinical care at the University Hospital for Infectious Diseases, Zagreb. The entire protease HIV-1 gene (PR, codons 1–99) and a part of the reverse transcriptase HIV-1 gene (RT, codons 1–240) were sequenced by using a validated in-house method. Mutations were determined by using Surveillance Drug Resistance Mutation list. HIV subtype was determined with Rega HIV-1 subtyping tool, version 3.0. Sequences subtyped as B were selected for phylogenetic inference. For each sequence in the dataset 10 closest sequences were determined with BLAST search. Phylogenetic trees were constructed with PhyML 3.0, while the Figtree version 1.4.3 was used for tree visualization. Transmission cluster were defined as sequences ≥3 patients from Croatian cohort with the approximate likelihood ratio test value >0.90. Results: Subtype B was found in 368 (91%) of patients. The overall prevalence of transmitted drug resistance (TDR) was 16.4% (n=66/403). The most prevalent TDR patterns were T215S, 7.2% (n=29/403) ; K101E, 3.5% (n=14/403) ; T215S + L210W, 2.2% (n=9/403) ; V32I+I47V+T215E/D+L100I+K103N, 1.9% (n=8/403) ; M41L+T215L, 0.7% (n=3/403). Phylogenetic analysis identified 19 local transmission clusters, of which 5 (26%) clusters were responsible for the forward spread of resistant HIV-1 viral strains. Patients in clusters (n=347) were more frequently MSM (319/358 vs. heterosexuals 24/39, p<0.001), of younger age (median:35 vs 39 years, p=0.02) and had a recent infection (77/81 vs. chronic 270/322 p=0.009). Conclusion: In this study we found a high prevalence of TDR and identified 5 local transmission clusters responsible for the spread of HIV-1 resistant strains

HIV-1 ; transmission ; clusters ; Croatia

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