ACQUIRED DRUG RESISTANCE TO NRTI CLASS IN TREATMENT-EXPERIENCED HIV INFECTED PATIENTS FROM THE CONSTANTA COUNTY: THERAPEUTIC IMPLICATIONS

Objective. To determine the prevalence of acquired drug resistance (ADR) and of resistance patterns in treatment-experienced HIV infected patients from Constanta in order to establish the best therapeutic options in NRTI class. Material and methods. A retrospective study which included 144 treatment-experienced HIV patients with confirmed viral failure. The strains isolated from these patients were analysed in the Molecular Genetic Laboratory of „Matei Bals“ National Institute of Infectious Diseases, Bucharest and the resulting sequences were saved in FASTA format. The HIV-1 subtyping was based on „REGA HIV01&2 Automated subtyping tool version 2.0“ algorithm. „Stanford HIVdb Program version 8.4“ was used in order to determine the therapeutic options. For statistical calculations, the R-Project software was used. Graphic representations were performed using GNUPLOT program. Results. The prevalence of the acquired drug resistance was 92.36%. The most frequent mutation occurred at the level of the codon 184. The TAM-2 path was more frequently selected compared to TAM-1. Association between TAM1 and TAM 2 were also found, mutation K65R being rarely met. Conclusions. The prevalence of the acquired drug resistance in our study was high, The most valuable therapeutic option in the INRT class remains tenofovir, due to the mutational profile, which was selected on account of the extensive use of thymidine analogues.

Inequality dynamics in the workplace among microbiologists and infectious disease specialists: a qualitative study in five European countries

OBJECTIVE

To explore the social, cultural, psychological and organizational factors associated with inequality in the workplace among clinical microbiologists (CM) and infectious disease (ID) specialists in European hospitals.

METHODS

We analysed data from 52 interviews and five focus groups involving 82 CM/ID specialists selected from university, research or community hospitals in five countries, one each in Northern, Western, Eastern, Southeastern and Southwestern Europe. The 80 hours of recordings were transcribed, and the anonymous database coding process was cross-checked iteratively by six researchers.

RESULTS

Inequality affects all the institutions in all the countries we looked at, denying or reducing access to professional assets with intensity and form that vary largely according to the cultural and organizational context. Discrimination is generally not explicit and uses disrespectful microbehaviours that are hard to respond to when they occur. Inequality affected also loans, distribution of research funds and gender and country representation in boards and conference faculty. Parenthood has a major impact on women's careers, as women are still mainly responsible for family care. Responses to discrimination range from reactive to surrender strategies.

CONCLUSIONS

Our study offers an effective model for diagnosing discriminatory behaviours in a medical professional setting. Knowledge of inequality's drivers could help national ID/CM societies in collaboration with major European stakeholders to further reduce such discrimination. The effect of discrimination on the quality of healthcare in Europe needs further exploration.

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.

Primary resistance to integrase strand-transfer inhibitors in Europe

OBJECTIVES

The objective of this study was to define the natural genotypic variation of the HIV-1 integrase gene across Europe for epidemiological surveillance of integrase strand-transfer inhibitor (InSTI) resistance.

METHODS

This was a multicentre, cross-sectional study within the European SPREAD HIV resistance surveillance programme. A representative set of 300 samples was selected from 1950 naive HIV-positive subjects newly diagnosed in 2006-07. The prevalence of InSTI resistance was evaluated using quality-controlled baseline population sequencing of integrase. Signature raltegravir, elvitegravir and dolutegravir resistance mutations were defined according to the IAS-USA 2014 list. In addition, all integrase substitutions relative to HXB2 were identified, including those with a Stanford HIVdb score ≥ 10 to at least one InSTI. To rule out circulation of minority InSTI-resistant HIV, 65 samples were selected for 454 integrase sequencing.

RESULTS

For the population sequencing analysis, 278 samples were retrieved and successfully analysed. No signature resistance mutations to any of the InSTIs were detected. Eleven (4%) subjects had mutations at resistance-associated positions with an HIVdb score ≥ 10. Of the 56 samples successfully analysed with 454 sequencing, no InSTI signature mutations were detected, whereas integrase substitutions with an HIVdb score ≥ 10 were found in 8 (14.3%) individuals.

CONCLUSIONS

No signature InSTI-resistant variants were circulating in Europe before the introduction of InSTIs. However, polymorphisms contributing to InSTI resistance were not rare. As InSTI use becomes more widespread, continuous surveillance of primary InSTI resistance is warranted. These data will be key to modelling the kinetics of InSTI resistance transmission in Europe in the coming years.

Epidemiology of hepatitis D in patients infected with hepatitis B virus in bucharest: a cross-sectional study

Epidemiological analyses indicate a decreasing level of hepatitis D (HDV) infections in most developed countries during the last 15 years. Romania, however, is one of the European countries that still has high morbidity from HDV; this study was performed in order to estimate the HDV prevalence in the Bucharest area. Three thousand four hundred sixty-one hepatitis B (HBV) infected patients were invited to participate and 1,094 were recruited. Serum anti-HDV IgG was detected in 223 patients indicating a hepatitis D seroprevalence of 20.4% (95% CI = 18.1-22.9) in patients chronically infected with HBV, less than that seen in previous studies. Seroprevalence was not gender related, but patients over 40 years were more likely to have anti-HDV antibodies, RR = 1.9 (1.2; 3.0). Detectable hepatitis D viraemia was found in 67.7% of the patients who were positive for anti-HDV. The HDV genotype was characterized for 40 isolates; all were very similar and belonged to genotype 1. Serum HBV-DNA was detectable less frequently in patients positive for anti-HDV than in patients infected with HBV alone: 68.5% versus 89.3%, OR 3.9 (1.7; 10.0), but the extent of this HDV replicative dominance varies with the sensitivity of the HBV-DNA detection. 19.3% of the subjects who tested positive for anti-HDV IgG had a HBV-DNA level higher than four logs. This high prevalence prompts the need for better HBV vaccination coverage and measures to prevent super infection with HDV in patients infected with HBV.

Evolution of the Sabin type 1 poliovirus in humans: characterization of strains isolated from patients with vaccine-associated paralytic poliomyelitis

Attenuated strains of the Sabin oral poliovirus vaccine replicate in the human gut and in rare cases cause vaccine-associated paralytic poliomyelitis (VAPP). Reversion of vaccine strains toward a pathogenic phenotype is probably one of the main causes of VAPP, a disease most frequently associated with type 3 and type 2 strains and more rarely with the type 1 (Sabin 1) strain. To identify the determinants and mechanisms of safety versus pathogenicity of the Sabin 1 strain, we characterized the genetic and phenotypic changes in six Sabin 1-derived viruses isolated from immunocompetent patients with VAPP. The genomes of these strains carried either few or numerous mutations from the original Sabin 1 genome. As assessed in transgenic mice carrying the human poliovirus receptor (PVR-Tg mice), all but one strain had lost the attenuated phenotype. Four strains presented only a moderate neurovirulent phenotype, probably due at least in part to reversions to the wild-type genotype, which were detected in the 5' noncoding region of the genome. The reversions found in most strains at nucleotide position 480, are known to be associated with an increase in neurovirulence. The construction and characterization of Sabin 1 mutants implicated a reversion at position 189, found in one strain, in the phenotypic change. The presence of 71 mutations in one neurovirulent strain suggests that a vaccine-derived strain can survive for a long time in humans. Surprisingly, none of the strains analyzed were as neurovirulent to PVR-Tg mice as was the wild-type parent of Sabin 1 (Mahoney) or a previously identified neurovirulent Sabin 1 mutant selected at a high temperature in cultured cells. Thus, in the human gut, the Sabin 1 strain does not necessarily evolve toward the genetic characteristics and high neuropathogenicity of its wild-type parent.

Point mutations involved in the attenuation/neurovirulence alternation in type 1 and 2 oral polio vaccine strains detected by site-specific polymerase chain reaction

One of the problems raised by the use of the attenuated oral poliovirus vaccine (OPV) Sabin strains is the genetic instability of the attenuated phenotype upon multiplication in vivo. Nucleotide sites critical for attenuation were identified for each of the three poliovirus serotypes. One important position lies in the 5' non-coding region of the genome of each of the three OPV strains, at nucleotide 480 in type 1, 481 in type 2 and 472 in type 3. Point mutations at these positions were usually selected upon multiplication in vivo as substitutions of the vaccine-type residue. The reversion was found to correlate with an increased degree of neurovirulence. To screen easily for this mutation in a great number of strains, we developed a site-specific polymerase chain reaction method based on the property of the Taq polymerase to elongate only primers with a perfect homology at the 3' extremity. We screened for this mutation in five type 1 and nine type 2 polio vaccine-derived strains isolated from vaccine-associated paralytic poliomyelitis (VAPP) cases and in 16 such strains isolated from healthy vaccinees. All 14 strains isolated from VAPP presented the reversion. Of the eight pairs of type 1 isolates from healthy vaccinees, four presented the reversion 3 days after vaccine administration and all but one at 7 days postvaccination. These results support the involvement of the 5' non-coding specific nucleotide sites in the reversion to neurovirulence of attenuated polio vaccine strains upon multiplication in the human gut.(ABSTRACT TRUNCATED AT 250 WORDS)

Polioviruses with natural recombinant genomes isolated from vaccine-associated paralytic poliomyelitis

To determine how oral poliovirus vaccine (Sabin) strains evolve during replication in humans and to confirm the etiology of vaccine-associated paralytic poliomyelitis (VAPP), we examined 70 vaccine-derived strains isolated from VAPP cases. Two distant sequences of the poliovirus genome were targeted for a double restriction fragment length polymorphism assay (RFLP) of reverse-transcribed genomic segments amplified by PCR, an extension of the method that we described previously (Balanant et al., 1991). One (RFLP-1) was a 480-long nucleotide sequence coding for the N-terminal part of the VP1 capsid polypeptide, situated in the 5' third of the viral genome (nucleotides 2401-2880). The other (RFLP-3D1) was a 291-long nucleotide sequence coding for a part of the viral polymerase, situated near the 3' end of the genome (nucleotides 6086-6376). Strain-specific restriction profiles could be generated for different field isolates by using three restriction enzymes in each case: HaeIII, DdeI, and HpaII for RFLP-1 and HaeIII, DdeI and RsaI for RFLP-3D1. With few exceptions, the vaccine-specific RFLP profiles were found to be conserved in both regions during replication of these viruses in humans. Thus, RFLP could be used as a marker so as to identify the origin of viral isolates at both ends of their genome. Whether viral isolates were vaccine-derived was determined by using strain-specific monoclonal antibodies and RFLP-1. Among the 70 isolates, 21 of the 43 type 2 strains and 15 of the 22 type 3 strains had a recombinant genome. None of the 5 type 1 Sabin-derived isolates was found to be recombinant. Both intertypic vaccine/vaccine and vaccine/non-vaccine recombinants were detected. Partial nucleotide sequencing confirmed the RFLP results in all cases that were investigated. In one case, it was possible to predict the recombination junction site from the restriction profiles. This site was more precisely localized by sequencing. The C6203 > U nucleotide substitution, which is suspected to contribute to the reversion toward neurovirulence of the attenuated Sabin 1 strain, was detected in almost all the recombinant genomes containing Sabin 1-specific sequences at the 3' extremity. This mutation was detected by identification of the modified RsaI profile in the RFLP-3D1. The results presented in this paper suggest that recombination, alone or together with mutation, might be one of the mechanisms of the reversion toward neurovirulence of attenuated vaccine strains and of the natural evolution of poliovirus.