High prevalence of non-B HIV-1 subtypes in seamen and their sexual partners in Croatia

Characterization of Human Immunodeficiency Virus-1 Transmission Clusters and Transmitted Drug-Resistant Mutations in Croatia from 2019 to 2022

Molecular epidemiology of HIV-1 infection is challenging due to the highly diverse HIV-genome. We investigated the genetic diversity and prevalence of transmitted drug resistance (TDR) followed by phylogenetic analysis in 270 HIV-1 infected, treatment-naïve individuals from Croatia in the period 2019-2022. The results of this research confirmed a high overall prevalence of TDR of 16.7%. Resistance to nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside RTIs (NNRTIs), and protease inhibitors (PIs) was found in 9.6%, 7.4%, and 1.5% of persons, respectively. No resistance to integrase strand-transfer inhibitors (INSTIs) was found. Phylogenetic analysis revealed that 173/229 sequences (75.5%) were part of transmission clusters, and the largest identified was T215S, consisting of 45 sequences. Forward transmission was confirmed in several clusters. We compared deep sequencing (DS) with Sanger sequencing (SS) on 60 randomly selected samples and identified additional surveillance drug resistance mutations (SDRMs) in 49 of them. Our data highlight the need for baseline resistance testing in treatment-naïve persons. Although no major INSTIs were found, monitoring of SDRMs to INSTIs should be continued due to the extensive use of first- and second-generation INSTIs.

High Prevalence of Non-B HIV-1 Subtypes in Overseas Sailors and Prostitutes in Korea

There have been no studies related to groups at the highest risk for HIV-1 infection in Korea before 1993. In this study, for the first time, we report the distribution of HIV subtypes in overseas sailors (OSs) and prostitutes who worked in brothels near U.S. military bases in Korea. We retrospectively determined the sequences of nef in 131 patients using reverse transcription polymerase chain reaction (RT-PCR). These patients composed of 102 OSs, 14 OS spouses, and 15 prostitutes. Phylogenetic analysis was performed using 128 Korean OSs, OS spouses, and prostitutes. The distribution of non-B subtypes (n = 105) was as follows: 39, CRF02_AG; 15, CRF01_AE; 7, A1; 7, A2; 6, D; 2, CRF06_cpx; 3, C; 6, G; 11, untypable; and 1 each for CRF09_cpx, CRF12_BF, CRF50_A1D, A3, AFG, H, F1, F2, and A. Of the 116 OSs and OS spouses, 101 (87%), 11 (9%), and 4 (3%) subjects had non-B, Western B, and Korean subclade B (KSB) HIV-1s, respectively. Among the 15 prostitutes, 10 had Western B (67%), 4 non-B (27%), and 1 KSB (7%) HIV-1s. All 14 couples, each comprising of an OS and his spouse, had the same subtype. KSB (5%) was detected in OSs and prostitutes in 1990 and 1994, respectively. Of the 131 patients analyzed in this study, 105 (80%), 21 (16%), and 5 (4%) were infected with the non-B, Western B, and KSB subtypes of HIV, respectively. In future, these data may provide an important foundation for analysis of HIV-1 subtypes in Korea.

Molecular epidemiology of HIV-1 infection in Europe: An overview

Human Immunodeficiency Virus type 1 (HIV-1) is characterised by vast genetic diversity. Globally circulating HIV-1 viruses are classified into distinct phylogenetic strains (subtypes, sub-subtypes) and several recombinant forms. Here we describe the characteristics and evolution of European HIV-1 epidemic over time through a review of published literature and updated queries of existing HIV-1 sequence databases. HIV-1 in Western and Central Europe was introduced in the early-1980s in the form of subtype B, which is still the predominant clade. However, in Eastern Europe (Former Soviet Union (FSU) countries and Russia) the predominant strain, introduced into Ukraine in the mid-1990s, is subtype A (A_FSU) with transmission mostly occurring in People Who Inject Drugs (PWID). In recent years, the epidemic is evolving towards a complex tapestry with an increase in the prevalence of non-B subtypes and recombinants in Western and Central Europe. Non-B epidemics are mainly associated with immigrants, heterosexuals and females but more recently, non-B clades have also spread amongst groups where non-B strains were previously absent - non-immigrant European populations and amongst men having sex with men (MSM). In some countries, non-B clades have spread amongst the native population, for example subtype G in Portugal and subtype A in Greece, Albania and Cyprus. Romania provides a unique case where sub-subtype F1 has predominated throughout the epidemic. In contrast, HIV-1 epidemic in FSU countries remains more homogeneous with A_FSU clade predominating in all countries. The differences between the evolution of the Western epidemic and the Eastern epidemic may be attributable to differences in transmission risk behaviours, lifestyle and the patterns of human mobility. The study of HIV-1 epidemic diversity provides a useful tool by which we can understand the history of the pandemic in addition to allowing us to monitor the spread and growth of the epidemic over time.

Phylogeographic analysis on the travel-related introduction of HIV-1 non-B subtypes to Northern Poland

Phylodynamic, sequence data based reconstructions for the surveillance of the geographic spatial spread are a powerful tool in molecular epidemiology. In this study region of origin for the set of 57 partial pol sequences derived from the patients the history of travel-related HIV transmission was analyzed using phylogeographic approach. Maximum likelihood trees based on the sets of country-annotated reference sequences were inferred for identified non-B variants. Region of sequence import was assigned using on the highest approximate likelihood ratios. Import of the A1 clades was traced to the Eastern Europe and associated with immigration from this region. Subtype C infections clustered most frequently with sequences of the South African origin while majority of subtype Ds were similar to the European clades. Subtype G sequences clustered with Portuguese lineage, CRF01_AE with Eastern or South-Eastern Asian. Eastern European, Middle African or Western African lineage was assigned for the CFR02_AG. Rare circulating recombinants originated either from Central Africa (CRF11_cpx - Democratic Republic of Congo, CRF13_cpx - Central African Republic, CRF37_cpx - Cameroon) or South America (CRF28_BF and CRF46_BF - Brazil). Import of the HIV-1 non-B variants, including recombinant forms previously rarely found in Poland and Europe is frequent among travelers. Observed founder events result in the heterosexually-driven introduction of the novel HIV-1 variants into the population.

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.

The emerging HIV epidemic among men who have sex with men in southeastern Europe

Patterns of HIV transmission in the seven countries of southeastern Europe (Albania, Bosnia and Herzegovina, Croatia, Montenegro, former Yugoslav Republic of Macedonia, Serbia and Slovenia) indicate that men who have sex with men (MSM) bear the highest burden of HIV. In 2008, MSM represented 56% of all HIV cases reported in Serbia, and 71 and 76% in Slovenia and Croatia, respectively. In other countries the number of reported HIV cases attributed to MSM remains low, which is likely due to under reporting. HIV prevalence measured in surveys was the highest among MSM compared with other at-risk groups, ranging from 0.7% in Bosnia and Herzegovina to 6.1% in Serbia. Data on sexual behaviors and HIV testing uptake indicate an urgent need to increase coverage with prevention services.

Frequency of HIV-1 viral load monitoring of patients initially successfully treated with combination antiretroviral therapy

Background

Although considered an essential tool for monitoring the effect of combination antiretroviral treatment (CART), HIV-1 RNA (viral load, VL) testing is greatly influenced by cost and availability of resources.

Objectives

To examine whether HIV infected patients who were initially successfully treated with CART have less frequent monitoring of VL over time and whether CART failure and other HIV-disease and sociodemographic characteristics are associated with less frequent VL testing.

Methods

The study included patients who started CART in the period 1999–2004, were older than 18 years, CART naive, had two consecutive viral load measurements of <400 copies/ml after 5 months of treatment and had continuous CART during the first 15 months. The time between two consecutive visits (days) was the outcome and associated factors were assessed using linear mixed models.

Results

We analyzed a total of 128 patients with 1683 visits through December 2009. CART failure was observed in 31 (24%) patients. When adjusted for the follow-up time, the mean interval between two consecutive VL tests taken in patients before CART failure (155.2 days) was almost identical to the interval taken in patients who did not fail CART (155.3 days). On multivariable analysis, we found that the adjusted estimated time between visits was 150.9 days before 2003 and 177.6 in 2008/2009. A longer time between visits was observed in seafarers compared to non-seafarers; the mean difference was 30.7 days (95% CI, 14.0 to 47.4; p<0.001); and in individuals who lived more than 160 kilometers from the HIV treatment center (mean difference, 16 days, p = 0.010).

Conclusions

Less frequent monitoring of VL became common in recent years and was not associated with failure. We identified seafarers as a population with special needs for CART monitoring and delivery.