Snjezana Zidovec Lepej

Transmission of HIV Drug Resistance and the Predicted Effect on Current First-line Regimens in Europe

Transmitted human immunodeficiency virus drug resistance in Europe is stable at around 8%. The impact of baseline mutation patterns on susceptibility to antiretroviral drugs should be addressed using clinical guidelines. The impact on baseline susceptibility is largest for nonnucleoside reverse transcriptase inhibitors.

Global Dispersal Pattern of HIV Type 1 Subtype CRF01_AE: A Genetic Trace of Human Mobility Related to Heterosexual Sexual Activities Centralized in Southeast Asia

BACKGROUND Human immunodeficiency virus type 1 (HIV-1) subtype CRF01_AE originated in Africa and then passed to Thailand, where it established a major epidemic. Despite the global presence of CRF01_AE, little is known about its subsequent dispersal pattern. METHODS We assembled a global data set of 2736 CRF01_AE sequences by pooling sequences from public databases and patient-cohort studies. We estimated viral dispersal patterns, using statistical phylogeographic analysis run over bootstrap trees estimated by the maximum likelihood method. RESULTS We show that Thailand has been the source of viral dispersal to most areas worldwide, including 17 of 20 sampled countries in Europe. Japan, Singapore, Vietnam, and other Asian countries have played a secondary role in the viral dissemination. In contrast, China and Taiwan have mainly imported strains from neighboring Asian countries, North America, and Africa without any significant viral exportation. DISCUSSION The central role of Thailand in the global spread of CRF01_AE can be probably explained by the popularity of Thailand as a vacation destination characterized by sex tourism and by Thai emigration to the Western world. Our study highlights the unique case of CRF01_AE, the only globally distributed non-B clade whose global dispersal did not originate in Africa.

Comparative Performances of HIV-1 RNA Load Assays at Low Viral Load Levels: Results of an International Collaboration

ABSTRACT Low-level viremia during antiretroviral therapy and its accurate measurement are increasingly relevant. Here, we present an international collaboration of 4,221 paired blood plasma viral load (pVL) results from four commercial assays, emphasizing the data with low pVL. The assays compared were the Abbott RealTime assay, the Roche Amplicor assay, and the Roche TaqMan version 1 and version 2 assays. The correlation between the assays was 0.90 to 0.97. However, at a low pVL, the correlation fell to 0.45 to 0.85. The observed interassay concordance was higher when detectability was defined as 200 copies/ml than when it was defined as 50 copies/ml. A pVL of ∼100 to 125 copies/ml by the TaqMan version 1 and version 2 assays corresponded best to a 50-copies/ml threshold with the Amplicor assay. Correlation and concordance between the viral load assays were lower at a low pVL. Clear guidelines are needed on the clinical significance of low-level viremia.

Seroprevalence, Risk Factors, and Hepatitis C Virus Genotypes in Groups With High-Risk Sexual Behavior in Croatia

The seroprevalence, risk factors and genotypes of hepatitis C virus (HCV) in groups with high‐risk sexual behavior (persons with multiple sexual partners, men who have sex with men, commercial sex workers and their clients and persons with sexually transmitted diseases) in seven Croatian cities were analyzed. A total of 821 participants without history of injecting drug use were included in the study. Anti‐HCV prevalence among risk groups varied from 2.9% to 8.5% with an overall prevalence of 4.6% (95% CI = 3.2–6.1) compared with 0.5% (95% CI = 0.0–1.5) in controls (pregnant females; OR = 9.66; 95% CI = 1.32–70.7). HCV‐RNA was detected in 73.1% anti‐HCV positive patients. Three of the seronegative cases (2.1%) were also found to be HCV‐RNA positive (“window period”). Genotype 1 was most commonly detected (55.6%). The most prevalent subtypes were 1a (38.9%) and 3a (38.9%). Sociodemographic characteristics (age, gender, marital status and level of education) were not associated with anti‐HCV seropositivity. Among sexually transmitted disease markers, a higher seroprevalence of HCV infection was found in subjects with a history of HBV infection (10.5% vs. 3.8%, P = 0.002) and gonorrhea (13.2% vs. 4.2%, P = 0.011). No other factors reflecting risk sexual behavior such as sexual orientation, number of sexual partners and number of risk behaviors were associated with HCV seroprevalence. J. Med. Virol. 81:1348–1353, 2009.

Prevalence of HIV and sexually transmitted infections and patterns of recent HIV testing among men who have sex with men in Zagreb, Croatia

Objective To determine the prevalence of HIV and other sexually transmitted infections (STIs) among men who have sex with men (MSM) in Zagreb, Croatia, and assess correlates of testing for HIV in the past 12 months. Methods The authors carried out a bio-behavioural survey using respondent-driven sampling (RDS) from September 2010 to February 2011. Participants completed a questionnaire and were asked to provide blood, urine, oropharyngeal and rectal swabs for the detection of infections. Data were analysed using RDS Analysis Tool 6.0.1 and STATA V.8.0. Results A total of 387 MSM were recruited at the University Hospital for Infectious Diseases. The age range of recruited men was 18–57 years. HIV prevalence was 2.8% (95% CI 1.1% to 5.1%) (3.6%, unadjusted), lower than that found in the first RDS survey carried out in 2006 (4.5%, 95% 2.2% to 7.3%) (4.9%, unadjusted). The seroprevalence of herpes virus type 2 was 5.9% (6.9, unadjusted) and that of syphilis measured by Treponema pallidum haemagglutination assay was 7.6% (6.7%, unadjusted). The authors found urethral and/or rectal infections with Chlamydia trachomatis in 7.2% (8.5%, unadjusted) of men and gonoccocal in 2.7% (2.1%, unadjusted). HIV testing in the past 12 months was reported by 32.7% (38.9%, unadjusted). In the multivariate analysis, significant correlates of recent HIV testing were having more than three partners in the past 12 months and the knowledge of HIV status of a regular partner. Conclusions The results indicate that there might have not been a progression of an HIV and STI epidemic in the past 5 years among MSM in Croatia. Prevention should expand by providing better uptake of HIV and STI testing services, thus enabling timely treatment.

Comparison between the Abbott RealTime High Risk HPV assay and the Hybrid Capture 2 assay for detecting high-risk human papillomavirus DNA in cervical specimens.

A total of 108 women were enrolled in the study whose cervical specimens were tested at the Educational Public Health Institute of Split and Dalmatia County. The presence of HPV DNA in the clinical samples was assessed based on the concordance between both assays. Discordant samples were further genotyped by using the INNO-LiPA HPV Genotyping Extra test (Innogenetics) at the University Hospital for Infectious Diseases in Zagreb.

Combined Analysis of the Prevalence of drug Resistant Hepatitis B Virus in antiviral therapy Experienced patients in Europe (CAPRE)

BACKGROUND European guidelines recommend treatment of chronic hepatitis B virus infection (CHB) with the nucleos(t)ide analogs (NAs) entecavir or tenofovir. However, many European CHB patients have been exposed to other NAs, which are associated with therapy failure and resistance. The CAPRE study was performed to gain insight in prevalence and characteristics of NA resistance in Europe. METHODS A survey was performed on genotypic resistance testing results acquired during routine monitoring of CHB patients with detectable serum hepatitis B virus DNA in European tertiary referral centers. RESULTS Data from 1568 patients were included. The majority (73.8%) were exposed to lamivudine monotherapy. Drug-resistant strains were detected in 52.7%. The most frequently encountered primary mutation was M204V/I (48.7%), followed by A181T/V (3.8%) and N236T (2.6%). In patients exposed to entecavir (n = 102), full resistance was present in 35.3%. Independent risk factors for resistance were age, viral load, and lamivudine exposure (P < .001). CONCLUSIONS These findings support resistance testing in cases of apparent NA therapy failure. This survey highlights the impact of exposure to lamivudine and adefovir on development of drug resistance and cross-resistance. Continued use of these NAs needs to be reconsidered at a pan-European level.

Cellular HIV-1 DNA levels in drug sensitive strains are equivalent to those in drug resistant strains in newly-diagnosed patients in Europe

Background HIV-1 genotypic drug resistance is an important threat to the success of antiretroviral therapy and transmitted resistance has reached 9% prevalence in Europe. Studies have demonstrated that HIV-1 DNA load in peripheral blood mononuclear cells (PBMC) have a predictive value for disease progression, independently of CD4 counts and plasma viral load. Methodology/Principal Findings Molecular-beacon-based real-time PCR was used to measure HIV-1 second template switch (STS) DNA in PBMC in newly-diagnosed HIV-1 patients across Europe. These patients were representative for the HIV-1 epidemic in the participating countries and were carrying either drug-resistant or sensitive viral strains. The assay design was improved from a previous version to specifically detect M-group HIV-1 and human CCR5 alleles. The findings resulted in a median of 3.32 log10 HIV-1 copies/106 PBMC and demonstrated for the first time no correlation between cellular HIV-1 DNA load and transmitted drug-resistance. A weak association between cellular HIV-1 DNA levels with plasma viral RNA load and CD4+ T-cell counts was also reconfirmed. Co-receptor tropism for 91% of samples, whether or not they conferred resistance, was CCR5. A comparison of pol sequences derived from RNA and DNA, resulted in a high similarity between the two. Conclusions/Significance An improved molecular-beacon-based real-time PCR assay is reported for the measurement of HIV-1 DNA in PBMC and has investigated the association between cellular HIV-1 DNA levels and transmitted resistance to antiretroviral therapy in newly-diagnosed patients from across Europe. The findings show no correlation between these two parameters, suggesting that transmitted resistance does not impact disease progression in HIV-1 infected individuals. The CCR5 co-receptor tropism predominance implies that both resistant and non-resistant strains behave similarly in early infection. Furthermore, a correlation found between RNA- and DNA-derived sequences in the pol region suggests that genotypic drug-resistance testing could be carried out on either template.

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.

Chemokine CXCL10 at Week 4 of Treatment Predicts Sustained Virological Response in Patients with Chronic Hepatitis C

The aim of this study was to analyze the predictive value of CXCL9, CXCL10, and CXCL11 concentrations before and after 4 and 12 weeks of treatment with pegylated interferon-α2b and ribavirin in patients with chronic hepatitis C infected with the hepatitis C virus genotype 1. The study included 46 adult patients (29 women and 17 men). Chemokine quantification in the serum was performed at baseline and after 1, 3, and 6 months of treatment by enzyme immunoassay. Chemokine responses were compared in patients achieving a sustained virological response to treatment (SVR, n=26) and the non-SVR group (n=20). The differences in the CXCL9 and CXCL10 concentrations between the SVR and non-SVR groups were statistically significant. A multivariant analysis showed a significant association between treatment failure and higher concentrations of CXCL10. A higher predictive value of CXCL10 concentrations after 4 weeks of treatment compared to pretreatment values has been found (area under the curve 0.9288 and 0.7942, respectively, P=0.016). CXCL10 concentrations above 250 pg/mL 4 weeks after the start of treatment were independently associated with non-SVR. In conclusion, the results of this study have shown that CXCL10 concentrations at the time of a rapid viral response (4 weeks) are better predictors of achieving SVR compared to baseline levels. Additionally, this study suggests an important role of CXCL9 as a biomarker of SVR in patients with chronic hepatitis C.