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.

Background. Numerous studies have shown that baseline drug resistance patterns may influence the outcome of antiretroviral therapy. Therefore, guidelines recommend drug resistance testing to guide the choice of initial regimen. In addition to optimizing individual patient management, these baseline resistance data enable transmitted drug resistance (TDR) to be surveyed for public health purposes. The SPREAD program systematically collects data to gain insight into TDR occurring in Europe since 2001.

Methods. Demographic, clinical, and virological data from 4140 antiretroviral-naive human immunodeficiency virus (HIV)–infected individuals from 26 countries who were newly diagnosed between 2008 and 2010 were analyzed. Evidence of TDR was defined using the WHO list for surveillance of drug resistance mutations. Prevalence of TDR was assessed over time by comparing the results to SPREAD data from 2002 to 2007. Baseline susceptibility to antiretroviral drugs was predicted using the Stanford HIVdb program version 7.0.

Results. The overall prevalence of TDR did not change significantly over time and was 8.3% (95% confidence interval, 7.2%–9.5%) in 2008–2010. The most frequent indicators of TDR were nucleoside reverse transcriptase inhibitor (NRTI) mutations (4.5%), followed by nonnucleoside reverse transcriptase inhibitor (NNRTI) mutations (2.9%) and protease inhibitor mutations (2.0%). Baseline mutations were most predictive of reduced susceptibility to initial NNRTI-based regimens: 4.5% and 6.5% of patient isolates were predicted to have resistance to regimens containing efavirenz or rilpivirine, respectively, independent of current NRTI backbones.

Conclusions. Although TDR was highest for NRTIs, the impact of baseline drug resistance patterns on susceptibility was largest for NNRTIs. The prevalence of TDR assessed by epidemiological surveys does not clearly indicate to what degree susceptibility to different drug classes is affected.

The early days of pandemic (H1N1) 2009 virus infection in the central region of Portugal

BACKGROUND

The first case of pandemic (H1N1) 2009 virus infection was diagnosed in the central region of Portugal on June 16, 2009, in a woman infected in Canada.

METHODS

The aim of our study was, first to characterize the clinical and epidemiologic aspects of all the patients with clinical manifestations included in the definition of case for investigation with samples submitted to diagnosis of the pandemic (H1N1) 2009 virus infection, in the central region of Portugal; second to assess the precision of the case definition of case for investigation considered in the study according to the presence or the absence of fever at the moment of clinical observation. We reviewed the medical records of all the patients presenting with Influenza like-illness classified as case for investigation and the first cases of patients infected with the new pandemic (H1N1) 2009 virus, diagnosed in the central region of Portugal during the pandemic period between June and August, 2009, were analyzed. Real-time reverse-transcriptase polymerase-chain-reaction (RT-PCR) testing was used to confirm the pandemic (H1N1) 2009 virus infection. Data collection was performed on a standardized paper format in agreement with the General Health Directorate.

RESULTS AND DISCUSSION

Pandemic (H1N1) 2009 virus infection was confirmed in 255 patients. Overall, median age was 23 years and 42.7 % were included in the category of 20 to 29 years. Confirmed infection in patients with less than 2 years or greater than 50 years was a rare event. The first cases were imported from Europe, namely France, Spain and England. On a second phase, pandemic (H1N1) 2009 virus infection was acquired in the south of Portugal (Algarve), before de diagnosis of the first domestic case. The incidence rate for pandemic (H1N1) 2009 virus infection was 10.7 per 100,000 persons and was different according to the district. It was higher in the district of Coimbra and Guarda were the main roads connecting to Europe are. The median calculated incubation period for the for pandemic (H1N1) 2009 virus infection was 2 days. The length of the clinical manifestations until the patients look for medical observation had a median time of 2 days. All the cases were of mild to moderate severity. No deaths were observed.

CONCLUSIONS

The early days of pandemic (H1N1) 2009 virus infection was mild in our region. Most affected patients were young adults, with the extreme categories ages of life being spared. Early detection and diagnosis, combined with stringent isolation and treatment procedures could have slowed the spread of the infection in our region.

Molecular epidemiology and prevalence of drug resistance-associated mutations in newly diagnosed HIV-1 patients in Portugal

BACKGROUND

Drug resistance transmission in newly diagnosed, drug-naïve HIV-1 infected individuals has been previously reported, with rates ranging from 5 to 27%. The aim of this study is to investigate the prevalence of resistance-associated mutations in drug-naïve, newly diagnosed patients, as well as monitoring the diversity of HIV-1 strains circulating in Portugal.

METHODS

One hundred eighty samples from newly diagnosed patients were prospectively collected during 2003, according to the distribution of HIV-1 infections in Portugal. Epidemiological, clinical and laboratory data was collected using a standardized form. Population sequencing was performed using an automated sequencer (ABI Prism 3100, Applied Biosystems) and a commercially available assay (ViroSeq HIV-1 Genotyping System, v2.0, Abbott). Stanford HIV Sequence Database was used for interpretation of resistance data; subtyping was performed using the REGA Subtyping Tool. When subtype was unassigned, further analysis was done using an alignment with reference sequences, and phylogenetic tools like Simplot and PHYLIP. Mutations listed by the International AIDS Society-USA were considered, except E44D and V118I.

RESULTS

Patient population included 124 males (69%) and 56 females (31%), the median age being 35. Western Europe was the main region of origin (77.2%), followed by Africa (18.3%), South America (2.8%) and Asia (1.1%). The most common route of transmission was heterosexual contact (54.4%), followed by intravenous drug use (20%), homo/bisexual individuals (19.4%) and blood transfusion (0.6%). The commonest subtypes were B (41.7%) and G (29.4%), while other non-B subtypes rated 12.8% and recombinant forms represented 16.1% of the samples. Fourteen patients (7.78%) were identified as carrying resistance-associated mutations. Ten were resistant to drugs from one class, three to drugs from two classes and one to drugs from all three classes. No statistically significant associations were found between age, gender, route of transmission, subtype and resistance.

CONCLUSIONS

The identification of newly diagnosed individuals carrying resistance-associated mutations confirms that drug resistance transmission is a public health problem in Portugal, with a possible impact on prevention, treatment and monitoring of HIV-1 infections.

Human immunodeficiency virus type 1 recombinant B/G subtypes circulating in Coimbra, Portugal

An increasing prevalence of HIV-1 non-B variants is being noticed in several European regions, particularly in countries such as Portugal, which have closer contacts with African endemic areas, where multiple HIV subtypes cocirculate. HIV-1 subtyping by phylogenetic analyses of reverse transcriptase, protease and env (C2-V3) genomic regions was carried out in plasma collected from 18 HIV-1-infected subjects living in Coimbra, Portugal, and suspected to be infected with non-B variants. Three (16.7%) subjects carried recombinant B/G viruses (BV3/BRT/Gpro; GV3/URT/Bpro; AV3/GRT/Bpro), whereas all the remaining individuals were infected with HIV-1 subtype B. This is the first report of recombinant B/G subtypes in Portugal.

[The treatment of cytomegalovirus retinitis in human immunodeficiency virus infection]

Most of the patients with immunodeficiency virus infection (75%-85%) are coinfected with cytomegalovirus. It is estimated that cytomegalovirus disease develops in 45% of them, mainly those presenting low CD4 cell counts (< 100/mm3). Retinitis is the most common manifestation of reactivated cytomegalovirus disease (85%), followed by other extra ocular sites (central nervous system, lungs, gastrointestinal system, adrenal glands, etc.). The particularly high incidence of cytomegalovirus retinitis, the difficulties concerning its therapeutical approach and the relatively unsatisfactory results, justify this review, according to the new treatment options presented in recent literature.