Distribution of hepatitis C virus genotypes and subtypes in Croatia: 2008-2015.

OBJECTIVE: Hepatitis C virus (HCV) genotyping is an important part of pre-treatment diagnostic algorithms as it guides the choice of therapeutic regimens. The aim of this study was to analyse the distribution of HCV genotypes in patients with chronic hepatitis C from Croatia in the period 2008-2015. METHODS: The study enrolled 3,655 anti-HCV positive patients with available results of HCV genotyping from the three largest national HCV genotyping laboratories. RESULTS: The majority of HCV-infected individuals enrolled in the study were male (70.7%). Analysis of age distribution in a subset of 2,164 individuals showed a mean age of 40.9 years (SD 11.77 years). Croatian patients were mostly infected with HCV genotype 1 (56.6%), followed by genotype 3 (37.3%), genotype 4 (4.2%) and genotype 2 (1.8%). Genotype 1 subtyping in a subset of 1,488 patients showed 54% (803/1,488) of 1b infections and 46% (685/1,488) of 1a infections. Percentages of genotype 1 were the highest in Central/Northwestern and Eastern Croatia and the lowest in the Central/Southern Adriatic Region. Genotype 3 was most frequently found in the Central/Southern Adriatic Region (49.1%) but represented only 17.5% of infections in Eastern Croatia (p < 0.001). CONCLUSIONS: The results of this nine-year retrospective analysis on the distribution of HCV genotypes and subtypes in 3,655 HCV-infected individuals from Croatia showed that the majority of infections can be attributed to genotypes 1 and 3 with absence of major changes in the molecular epidemiology of the two most frequent HCV genotypes infection in Croatia in the past 20 years.

The prevalence of transmitted drug resistance in newly diagnosed HIV-infected individuals in Croatia: the role of transmission clusters of men who have sex with men carrying the T215S surveillance drug resistance mutation.

The aim of this study was to determine the prevalence of transmitted drug resistance (TDR) in newly diagnosed and treatment-naive HIV-infected patients from Croatia and evaluate a possible contribution of transmission clusters to the spread of resistant virus. The study enrolled treatment-naive HIV-infected patients that entered clinical care at the Croatian Reference Center for HIV/AIDS between 2006 and 2008. The protease gene and a part of the reverse transcriptase gene of the HIV-1 genome were sequenced by using the Trugene HIV-1 Genotyping System. The prevalence of transmitted drug resistance was analyzed by using the surveillance drug resistance mutations (SDRM) list recommended by the WHO in 2009. We report findings for 118 of 180 eligible patients (65.6% coverage). SDRM were detected in 26 of 118 patients (22.0%) who were infected with subtype B and belonged mostly to the men having sex with men (MSM). The majority of patients with primary resistance carried SDRM associated with resistance to nucleoside analogues reverse transcriptase inhibitors (NRTIs, 23 of 118 patients, 19.5%). The most frequently found NRTI SDRM was T215S (17 of 118 patients, 14.4%). SDRM associated with resistance to nonnucleoside reverse transcriptase inhibitors were detected in three (2.5%) patients and primary resistance to protease inhibitors was not detected. Non-B subtypes were detected in 13/118 patients (11%). A total of 12 transmission pairs and eight distinct transmission clusters were identified with the largest cluster harboring sequences from 19 patients; among them all but two were carrying the T215S mutation. This study showed a high prevalence of TDR in newly diagnosed MSM from Croatia and is an important contribution concerning the relationship between local transmission clusters and the spread of resistant virus.

Phylogenetic analysis of HIV sequences obtained in a respondent-driven sampling study of men who have sex with men.

The presence of transmission clusters and their relationship to the recruitment chain were investigated in an HIV prevalence assessment survey using respondent-driven sampling among men who had sex with men (MSM) in Zagreb, Croatia. HIV infection was found in 18 of 360 participants. Five individuals belong to a transmission cluster of MSM infected with phylogenetically related HIV. All were recruited in later waves (fourth to ninth), suggesting that the population is sexually networked.