Análisis genético de las mutaciones presentes en las poblaciones virales en pacientes con infección por VIH-1 en Ecuador / Genetic analysis of the mutations in HIV-1 infected population in Ecuador

Resumen Introducción Las recomendaciones internacionales de tratamiento anti-retroviral incluyen pruebas de resistencia para orientar el régimen de tratamiento en cada paciente, lo que no está disponible de forma estable en Ecuador. Objetivo Describir las mutaciones que confieren resistencia a anti-retrovirales en una población de pacientes ecuatorianos. Metodología A partir de muestras de plasma de 101 pacientes con VIH-1 con fallo a la terapia anti-retroviral, 15 niños y 86 adultos, se realizó pirosecuenciación con el GS Junior (Roche) y se analizaron las secuencias con el programa DeepChek. Resultados Las mutaciones más frecuentes fueron M184V/I, K101E/P/H, K103N/S, D30N, M46L/I, I54L/M, V82T/F/A/S/L y L90M en adultos, y F77L, K103N/S, M46L/I, V82T/F/A/S/L y L90M en niños. Se encontró una elevada resistencia a los inhibidores de la transcriptasa reversa (TR) no análogos de nucleósidos en poblaciones minoritarias virales de adultos y niños (34,9 y 70%, respectivamente), en los niños, tanto las poblaciones virales mayoritarias como minoritarias, fueron resistente a inhibidores de proteasa (> 45%). Los pacientes que tuvieron un mayor número de esquemas terapéuticos presentaron mayores niveles de resistencia a los anti-retrovirales. La mayoría de las muestras fueron del subtipo B en la región de la TR y proteasa, y CRF25_cpx en integrasa. Conclusiones Se muestran las mutaciones y la resistencia a antiretrovirales en una población de pacientes ecuatorianos con infección por VIH-1, que permitirán realizar un llamado de alerta a las autoridades de salud sobre la necesidad de realizar estudios de resistencia.

Background The international recommendations of antiretroviral treatment include resistance tests to guide the treatment regimen in each patient, which is not available on a regular basis in Ecuador. Aim To describe mutations that confer resistance to antiretrovirals in a population of Ecuadorian patients. Methods Plasma samples from 101 HIV-1 patients with failure to antiretroviral therapy, divided into 15 children and 86 adults, were studied with the GS Junior (Roche) and the sequences were analyzed with the DeepChek program. Results The most frequent mutations were M184V/I, K101E/P/H, K103N/S, D30N, M46L/I, I54L/M, V82T/F/A/S/L and L90M in adults and F77L, K103N/S, M46L/I, V82T/F/A/S/L and L90M in children. High resistance to non-nucleoside reverse transcriptase (RT) inhibitors in minority viral populations of adults and children (34.9% and 70%) was detected; in children both viral populations (majority and minority viral populations) (> 45%) were protease inhibitor resistant. Patients who had a greater number of therapeutic regimens had higher levels of resistance to antiretrovirals. Most of the samples were subtype B in the TR and protease region, and CRF25_cpx in integrase. Conclusions Mutations and resistance to antiretrovirals are shown in a population of Ecuadorian patients with HIV-1. These results will make it possible to issue a warning to health authorities about the need for resistance studies.

Trends and predictors of HIV-1 acquired drug resistance in Minas Gerais, Brazil: 2002-2012

Abstract Several studies show that the prevalence of multidrug-resistant HIV-1 virus is declining over time. A retrospective cohort study was carried out to evaluate the trends of drug resistance in antiretroviral treatment-exposed individuals in a state of a middle-income country, Minas Gerais, southeast region of Brazil. We analyzed 2115 HIV-1 sequences from 2002 up to 2012, from 52 cities of Minas Gerais. The groups were analyzed according to the definitions: "IAS – 3 class mutations", if ≥1 drug resistance mutation from IAS 2015 list (DRM) was present in each class; "No fully susceptible drugs" as the absence of any fully susceptible drug in Stanford algorithm; and "GSS ≥ 2″, when a maximum calculated GSS (genotypic susceptibility score) was ≥2 or ≥3, counting only drugs available in Brazil and USA at given calendar years. Time trends of resistance were analyzed by Cochran–Armitage test. We observed a decrease in the rate resistance mutations for PI, NRTI, "IAS – 3 class mutations", and "No fully susceptible drugs" over these 11 years, from 69.2% to 20.7%, 92.3% to 90.2%, 46.2% to 22.5%, and 12.8% to 5.7%, respectively (p < 0.05). Resistance to NNRTI increased from 74.4% to 81.6%, mainly because of K103N mutation. The GSS score ≥2 increased during the years from 35.9% to 87.3% (p < 0.001). We demonstrate that resistance to PI and to the three main classes simultaneously are declining, although the number of patients on of antiretroviral therapy has doubled in the last ten years in Brazil (125,000 in 2002 to 400,000 in 2014). Broader resistance testing and the availability of more therapeutic options might have influenced this decline. The increase in NNRTI resistance can limit this class as first line treatment in Brazil in the future.

Enterotoxin genes, multidrug resistance, and molecular typing of Staphylococcus spp. isolated from organic bovine milk / Genes de enterotoxinas, multirresistência a antimicrobianos e caracterização molecular de espécies de Staphylococcus spp. isoladas de leite bovino orgânico

The multidrug resistant and the emergence of methicillin-resistant staphylococci isolated from animals, food, and humans are public health concern. These microorganisms produce different toxins related to food poisoning in humans. This study aimed to characterize Staphylococcus spp. isolated from two organic milk farms in Brazil. A total of 259 milk samples were collected, from which 58 (22.4%) Staphylococcus spp. were isolated. The highest sensibility to ceftiofur and sulfamethoxazole/trimethoprim was observed in 96.6% of Staphylococcus spp., and whereas 89% were resistant to penicillin G. The mecA gene was detected in 13.8% of the isolates. SEA and SEC were the most common enterotoxins detected. PFGE revealed genetic heterogeneity from S. intermedius and S. warneri analyzed, while S. aureus presented similar profiles among isolates from the two studied herds. To the best of our knowledge, the current study describes for the first time presence of enterotoxins, mecA gene, and genetic diversity of staphylococci isolated from organic dairy farms in Brazil.(AU)

A emergência de estafilococos multirresistentes e resistentes à meticilina, isolados de animais, alimentos e humanos é uma preocupação em saúde pública. Esses micro-organismos produzem diferentes toxinas relacionadas à intoxicação alimentar em humanos. Este estudo caracterizou Staphylococcus spp. isolados em duas fazendas orgânicas no Brasil. Foram coletadas 259 amostras de leite em duas propriedades leiteiras orgânicas, nas quais 58 (22,4%) estirpes de Staphylococcus spp. foram isoladas. A maior sensibilidade dos isolados foi observada para ceftiofur e sulfametoxazol/trimetoprim em 96,6%. Em contraste, acima de 89% de resistência dos estafilicocos foi encontrada para penicilina G. O gene mecA foi identificado em 13,8% dos isolados. SEA e SEC foram as enterotoxinas mais comumente detectadas. PFGE revelou heterogeneidade genética entre S. intermedius e S. warneri, enquanto S. aureus demonstraram perfis semelhantes entre isolados dos dois rebanhos estudados. Relata-se pela primeira vez no Brasil a detecção de enterotoxinas, o gene mecA e diversidade genética em estafilococos isolados de vacas em produção orgânica.(AU)

Eficacia y seguridad del uso de maraviroc para el tratamiento de VIH-1 con tropismo ccr5 positivo, en pacientes multidrogorresistentes en estadio sida / Efficacy and safety of the use of maraviroc for the treatment of HIV-1 with ccr5 positive tropism in multidrug-resistant patients in AIDS stage

INTRODUCCIÓN: Antecedentes: El presente dictamen presenta la evaluación de tecnología de la eficacia y seguridad de maraviroc para el tratamiento de pacientes infectados con VIH01 con tropismo CCR5 positivo, multidrogorresistentes, en estadio SIDA. Aspectos Generales: Hacia el final de 2014, alrededor de 36.9 millones de personas en el mundo vivian con VIH. De estas, aproximadamente 1.2 millones murieron por causas relacionadas al VIH ese mismo año. Las terapias antirretrovirales han permitido reducir el número de muertes en un 42% desde el 2004. Tecnología Sanitaria de Interés: Maraviroc es un antagonista del receptor de quimoquina C-Ctipo 5 (CCR5 por sus siglas en inglés) en las membranas de los linfocitos CD4. El receptor CCR5, junto con el receptor de quimioterapina C-X-C tipo 4 (CXCR4 por sus siglas en inglés), son los co´receptores más relevantes en la infección con VIH-1, ya que permiten la fusión de las membranas celular y viral, y la consecuente entrada del ARN viral al citoplasma. METODOLOGIA: Se llevó a cabo una búsqueda de la literatura con respecto a la eficacia y seguridad de maraviroc para el tratamiento de VIH-1 con tropismo CCR5 positivo, en pacientes multidrogorresistentes en las bases de datos de PubMed, TRIPDATABASE y www.clinicaltrials.gov. Adicionalmente, se realizó una búsqueda de evaluaciones de tecnologías y guías de práctica clínica en las páginas web de gruposdedicados a la investigación y educación en salud en general como The National Institute for Health and Care Excellence (NICE) y The USA Department of human and health services (DHHS); y especializados en VIH como The British HIV Association (BHIVA), The International \r\nAntiviral Society (IAS), The British Columbia Centre for Excellence in HIV/AIDS (BC-CfE) y The European AIDS Clinical Society. RESULTADOS: Sinopsis de la Evidencia: se llevó a cabo una búsqueda de evidencia científica relacionada al uso de maraviroc como tratamiento de pacientes infectados con VIH-1 con tropismo CCR5, multidrogorresistentes y en estadio SIDA. En la presente sinopsis se describe la evidencia disponible según el tipo de publicación, siguiendo lo indicado en los criterios de elegibilidad (GPC, ETS, RS, MA y ECA fase III). CONCLUSIONES: A la fecha (Mayo 2016) no existe evidencia de ensayos clínicos en fase III que \r\ncomparen directamente la eficacia y seguridad de maraviroc vs enfuvirtide en la población de pacientes con SIDA, multidrogorresistentes e infectados con VIH-1 con tropismo CCR5 positivo. Sin embargo, se toma como evidencia indirecta dos ensayos clínicos multicéntricos de fase III que evaluaron la eficacia y seguridad de maraviroc en comparación con placebo, y un posterior análisis de sub-grupo de los mismos, así como estudios sobre los eventos adversos relacionados al uso de enfuvirtide. El Instituto de Evaluación de Tecnologías Sanitarias-IETSI, aprueba por el periodo de 2 años a partir de la fecha de publicación del presente \r\nFiesT Es. dictamen preliminar, el uso de maraviroc para el tratamiento de pacientes infectados con VIH-1 con tropismo CCR5 positivo, multidrogorresistentes y en estadio SIDA, ya que se ha demostrado su eficacia en dicha sub-población de pacientes con VIH-1, y representa un beneficio para la calidad de vida de estos pacientes y un menor costo para la institución.

Analysis of Reverse Transcriptase Gene Mutations in the Hepatitis B Virus at a University Hospital in Korea

BACKGROUND: Most mutations in the reverse transcriptase (RT) gene of the hepatitis B virus (HBV) are related to resistance to antiviral agents. Cross-sectional studies on the mutations of this gene are rare. Thus, we analyzed the mutation patterns of RT genes and their biochemical parameters. METHODS: From 2009 to 2012, 301 blood specimens from patients with chronic hepatitis B at Daegu Catholic University Medical Center were retrospectively analyzed for the RT gene sequence of HBV, ALT, hepatitis B e antigen (HBeAg), and HBV DNA. The mutation patterns of the RT gene were compared with the biochemical parameters. RESULTS: Of the 301 patients, 100 (33.2%) had no RT gene mutations. The remaining showed the following mutation patterns: rtM204I/V (50.2%), rtL180M (39.2%), and rtA181T/V (19.6%). Combined mutations were found in 146 cases (48.5%). Of these, the combination of amino acid changes at rt180+rt204 (49.3%) was most frequently detected, followed by rt181+rt236 (11.0%) and rt173+rt180+rt204 (9.6%). In the mutated group, HBV DNA and HBeAg positive rates were significantly higher (P<0.05 for both). Phenotypic analysis showed that lamivudine resistance was most frequently detected (34.6%), followed by adefovir resistance (15.6%). Multidrug resistance was detected in 48 cases (15.9%). The adefovir-resistant group had a higher proportion of cases with HBV loads greater than 2,000 IU/mL. CONCLUSIONS: We found correlations between the mutation status of the RT domain and biochemical parameters such as HBV DNA and HBeAg positive rate. The presence of RT gene mutations could therefore be utilized to predict clinical status.

Fatores que levam a não adesão dos pacientes em tratamento com antirretrovirais / Factors that lead to noncompliance in patients antiretroviral therapy

Os antirretrovirais utilizados no tratamento da AIDS trouxeram benefícios na sobrevida dos pacientes, entretanto a não adesão terapêutica está relacionada com o desenvolvimento de resistência viral, levando a falência da terapia e disseminação de vírus resistente. O objetivo desta pesquisa foi analisar os fatores que levam a não adesão dos pacientes em tratamento. Foram analisados 26 pacientes, através de entrevista estruturada, dados clínicos laboratoriais e fichas de dispensação da farmácia. Houve um predomínio para o sexo masculino, baixa escolaridade, solteiro(a), com renda familiar de 1 salário mínimo, a média da idade foi de 41 anos, o tempo de uso da terapia ART obteve uma média de 51,88 meses, metade dos pacientes já mudaram de esquema terapêutico. Na contagem de linfócitos T CD4+, 11,5% tiveram valores abaixo de 200 e 57,5% apresentaram níveis indetectáveis de carga viral. Na análise dos dados obtidos na farmácia, 16,04% atrasaram a retirada da medicação. Quando correlacionado os dados, 23,1% dos pacientes não apresentaram boa adesão terapêutica. Dentre os fatores relacionados, estão: menor escolaridade, desemprego, achar que não necessita do tratamento, usuários de drogas, complexidade terapêutica, adequação de rotina e estilo de vida. Deve se estabelecer estratégias que melhorem a adesão ao tratamento.

The antiretroviral drugs used in AIDS treatment have benefits on patient survival, but not the adherence therapy is related to the development of viral resistance, leading to failure of therapy and spread of resistant virus. The objective of this research was to analyze the factors leading to non-adherence of patients to treatment. We analyzed 26 patients using a structured interview, clinical laboratory and pharmacy dispensing tokens. There was a predominance of male sex, low education, single (a), with a family income of minimum wage, the average age was 41 years, the time of use of ART therapy achieved an average of 51.88 months, half patients have already changed the treatment regimen. In the CD4 lymphocyte count, 11.5% had values below 200 and 57.5% had undetectable viral load. In analyzing the data obtained in the pharmacy, 16.04% have delayed the withdrawal of medication. When correlated data, 23.1% of patients with poor adherence. Among the related factors include: lower education, unemployment, find that you do not need treatment, drug users, complexity of therapy, fitness routine and lifestyle. Should develop strategies to improve adherence to treatment.

In vitro assessment of drug resistance in Plasmodium falciparum in five States of India.

Background & objectives: In vitro assays are an important tool to assess baseline sensitivity and monitor the drug response of Plasmodium falciparum over time and place and, therefore, can provide background information for the development and evaluation of drug policies. This study was aimed at determining the in vitro sensitivity of P. falciparum isolates to antimalarials. Methods: The in vitro activity of 108 P. falciparum isolates obtained from five States of India was evaluated using WHO microtest (Mark III) to chloroquine, monodesethylamodiaquine, dihydroartesunate and mefloquine. Samples were collected from the States of Orissa, Jharkhand, Karnataka, Goa and Chhattisgarh from September 2007 to August 2009. In addition, representative samples from different States of India cryopreserved and culture adapted in the Malaria Parasite Bank of National Institute of Malaria Research, New Delhi, were also evaluated. Results: The proportion of isolates resistant to chloroquine and monodesethylamodiaquine was 44.4 and 25 per cent, respectively. Of the 27 isolates resistant to monodesethylamodiaquine, 16 (59.3%) were cross-resistant to chloroquine. No isolate showed resistance to dihydroartesunate and mefloquine. Isolates from Orissa showed the highest degree of resistance to chloroquine and amodiaquine followed by Jharkhand. Forty two isolates were genotyped for pfcrt T76K chloroquine resistant mutation; mutations were seen in 38 (90.47%) isolates. Interpretation & conclusions: The Indian P. falciparum isolates showed a high degree of resistance to chloroquine followed by monodesethylamodiaquine. No resistance was recorded to mefloquine and dihydroartesunate.

High efficacy of adefovir and entecavir combination therapy in patients with nucleoside-refractory hepatitis B / 대한간학회지

BACKGROUND/AIMS: Newly developed and potent antiviral agents suffer from the problem of drug resistance. Multidrug resistance is a major impediment in the treatment of patients with chronic hepatitis B (CHB). In line with American Association for the Study of Liver Diseases guidelines, adefovir dipivoxil (ADV) add-on therapy is recommended in the case of lamivudine resistance, while tenofovir disoproxil fumarate (TDF) is recommended for ADV or entecavir (ETV) resistance. TDF is currently not available in Korea. ADV+ETV combination therapy may be a viable alternative to TDF in patients with either ADV or ETV resistance. However, the efficacy of ADV+ETV combination therapy in patients with CHB and multidrug resistance is unclear. This study investigated the efficacy of ADV+ETV combination therapy in patients with multidrug resistance. METHODS: Twenty-five patients were enrolled and were administered ADV+ETV combination therapy for at least 6 months. Blood was drawn at baseline and at 3, 6, 9, and 12 months after commencing treatment, and the following blood parameters were analyzed: alanine transaminase, hepatitis B e-antigen (HBeAg), anti-hepatitis B e-antigen, and hepatitis B virus (HBV) DNA levels. The initial virological response (IVR) was defined as an HBV DNA level of or =5.0 log) dropped from 76% at baseline to only 5% after 6 months of treatment. The biochemical response rate during the first 6 months was 71%. HBeAg was lost in 2 patients (10%). CONCLUSIONS: ADV+ETV combination therapy induced a good IVR in CHB patients who were refractory to more than 2 antiviral agents. This regimen may be a good alternative to TDF in Korea, where that drug is not available.

Simultaneous detection of hepatitis B virus genotypes and mutations associated with resistance to lamivudine, adefovir, and telbivudine by the polymerase chain reaction-ligase detection reaction

OBJECTIVES: Detection of mutations associated to nucleos(t)ide analogs and hepatitis B virus (HBV) genotyping are essential for monitoring treatment of HBV infection. We developed a multiplex polymerase chain reaction-ligase detection reaction (PCR-LDR) assay for the rapid detection of HBV genotypes and mutations associated with lamivudine, adefovir, and telbivudine resistance in HBV-infected patients. METHODS: HBV templates were amplified by PCR, followed by LDR and electrophoresis on a sequencer. The assay was evaluated using plasmids that contained wild-type or mutant HBV sequences and 216 clinical samples. RESULTS: The PCR-LDR assay and sequencing gave comparable results for 158 of the 216 samples (73.1 percent) with respect to mutation detection and genotyping. Complete agreement between the two methods was observed for all the samples (100 percent) at codon 180 and codon 204. Concordant results were observed for 99.4 percent of the 158 samples at codon 181 and 98.7 percent at codon 236. The genotyping results were completely concordant between the PCR-LDR assay and sequencing. The PCR-LDR assay could detect a proportion of 1 percent mutant plasmid in a background of wild-type plasmid. CONCLUSION: The PCR-LDR assay is sensitive and specific for detection of HBV genotypes and drug resistance mutations, and could be helpful for decision making in the treatment of HBV infection.

Virological surveillance and antiviral resistance of human influenza virus in Argentina, 2005–2008 / Vigilancia virológica y resistencia a los antivíricos del virus de la gripe humana en la Argentina, 2005–2008

Objective. To describe the virological characteristics of the influenza strains circulating in Argentina in 2005–2008 and to assess the prevalence of antiviral resistance. Methods. On the basis of their geographical spread and prevalence, influenza A and B isolates grown in Madin–Darby canine kidney cells were selected after antigenic and genomic characterization to be analyzed for antiviral resistance by enzymatic assay and pyrosequencing. Amantadine susceptibility was evaluated by pyrosequencing for known resistance markers on 45 strains of influenza A. Susceptibility to oseltamivir and zanamivir was evaluated by enzymatic assay of 67 influenza A and 46 influenza B strains, some of which were further analyzed by sequencing the neuraminidase gene. Results. Resistance to amantadine was observed only on A(H3N2) strains (29/33); all of them carried the mutation S31N in their M2 sequence. Oseltamivir resistance was observed in 12 (34.3%) of the 35 A(H1N1) strains from 2008; all of them carried the mutation H275Y in their neuraminidase sequence. All these viruses remained sensitive to zanamivir. Conclusions. This study describes a high incidence of amantadine-resistant influenza A(H3N2) viruses since 2006 and an unprecedented increase in oseltamivir resistance detected only in influenza A(H1N1) viruses isolated in 2008. Influenza A and B viruses were more sensitive to oseltamivir than to zanamivir, and influenza A viruses were more sensitive to both neuraminidase inhibitors than the influenza B viruses. The national data generated and analyzed in this study may help increase knowledge about influenza antiviral drug resistance, which is a problem of global concern.

Objetivo. Describir las características virológicas de las cepas de virus de la gripe que circulaban en la Argentina entre el 2005 y el 2008, y evaluar la prevalencia de la resistencia a los antivíricos. Métodos. Según su diseminación geográfica y su prevalencia, se seleccionaron aislados de gripe A y B cultivados en células renales caninas de Madin-Darby después de su caracterización antigénica y genómica, y se analizó su resistencia a los antivíricos mediante análisis enzimático y pirosecuenciación. La sensibilidad a la amantadina se evaluó por pirosecuenciación para los marcadores conocidos de resistencia en 45 cepas de gripe A. La sensibilidad al oseltamivir y al zanamivir se evaluó mediante análisis enzimático de 67 cepas de gripe A y 46 cepas de gripe B, algunas de las cuales se analizaron en mayor profundidad mediante la secuenciación del gen de la neuraminidasa. Resultados. Se observó resistencia a la amantadina solo en las cepas de gripe A (H3N2) (29/33); todas ellas tenían la mutación S31N en su secuencia de M2. Se observó resistencia al oseltamivir en 12 (34,3%) de las 35 cepas de gripe A (H1N1) aisladas en el 2008; todas ellas tenían la mutación H275Y en su secuencia de neuraminidasa. Todos estos virus conservaron su sensibilidad al zanamivir. Conclusiones. En este estudio se describe una incidencia elevada del virus de la gripe A (H3N2) resistente a la amantadina desde el 2006 y un aumento sin precedentes de la resistencia al oseltamivir detectada solo en los virus de la gripe A (H1N1) aislados en el 2008. Los virus de la gripe A y B fueron más sensibles al oseltamivir que al zanamivir y los virus de la gripe A fueron más sensibles a ambos inhibidores de la neuraminidasa que los virus de la gripe B. Los datos nacionales generados y analizados en este estudio pueden ayudar a aumentar los conocimientos acerca de la resistencia a los fármacos antivíricos dirigidos contra el virus de la gripe, lo que es un motivo de preocupación mundial.

The impact of the nelfinavir resistance-conferring mutation D30N on the susceptibility of HIV-1 subtype B to other protease inhibitors

The human immunodeficiency virus type 1 (HIV-1) protease mutation D30N is exclusively selected by the protease inhibitor (PI) nelfinavir and confers resistance to this drug. We demonstrate that D30N increases the susceptibility to saquinavir (SQV) and amprenavir in HIV-1 subtype B isolates and that the N88D mutation in a D30N background neutralizes this effect. D30N also suppresses indinavir (IDV) resistance caused by the M46I mutation. Interestingly, in patients with viruses originally containing the D30N mutation who were treated with IDV or SQV, the virus either reversed this mutation or acquired N88D, suggesting an antagonistic effect of D30N upon exposure to these PIs. These findings can improve direct salvage drug treatment in resource limited countries where subtype B is epidemiologically important and extend the value of first and second line PIs in these populations.

Genotype and antiretroviral drug resistance of human immunodeficiency virus-1 in Saudi Arabia

To analyze antiretroviral drug resistance and determine the genotype of human immunodeficiency virus [HIV]-l in Saudi patients by sequencing an amplified region of the viral pol gene. This retrospective study analyzed data from plasma samples submitted for genotypic drug sensitivity monitoring. Samples were analyzed at the Special Infectious Agent Unit, King Fahd Medical Research Center of King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia from August 2004 to June 2009. The Viroseq2.5 kit [Celera/Abbott] was used with ABI Prism 3100 sequencer. All patients were Saudi nationals and were on antiretroviral therapy, some experiencing treatment failure. Based on protease region [PR], genotypes of 63 samples were as follows: C:22, G:21, B:9, CRF02_AG:5, D:3, A:l, F:l, and J:l. Based on reverse transcriptase region [RT], genotypes were as follows: C:23, G:24, B:9, CRF02 AG: 2, D:2, A:l, and F:l. Antiretroviral susceptibility testing results were as follows: 52% of the isolates were susceptible to all 3 major classes of antiretroviral drugs used, 41% had mutations known to confer high level resistance to one or more of the nucleoside analogue reverse transcriptase inhibitors, 16% had mutations known to confer high level resistance to non-nucleoside analogues reverse transcriptase inhibitors, 13% had mutations known to confer high level resistance to one or more of the protease inhibitors [PI]. Most isolates were susceptible to 2 or at least one class of antiretroviral, and only 3% of the isolates had resistance to several members of all 3 classes. Antiretroviral resistance is not uncommon in Saudi patients on antiretroviral therapy

Genotypic correlation of a virologic response to lamivudine, stavudine and nevirapine in patients for whom combination therapy had failed

Resistance is the consequence of mutations that emerge in the viral proteins targeted by antiretroviral agents. Thus, we focused our attention on mutations in HIV-1 reverse transcriptase to define their association with specific NRTIs and NRTI resistance mutations at therapeutic failure. The study population included 5 Iranian HIV-positive patients referring to Counseling Behavioral Modification Center in Shiraz who received a combination of antiretroviral therapy [lamivudine, stavudine and nevirapine]. PBMC DNA was isolated from blood and PCR was performed to produce a 1200 bp amplicon and resolved by electrophoresis on a 0.7% agarose TBE gel, visualized with ethidium bromide. PCR products from HIV-1-infected patients were cloned into pCR2.1TOPO, then sequenced. Finally, sequence data were analyzed. Results showed drug resistance in 2 patients, of whom one had NNRTI resistance mutations [M230G, L234R and K238H] and other had both NRTI [V75M] and NNRTI [F227L] resistance mutations. Confirmation of genetic resistance in HIV-positive patients who show therapy failure can help physicians to change their drug regime in order to achieve better outcome

Two Cases of Multidrug-Resistant Human Immunodeficiency Virus Infection Treated with Atazanavir and Lopinavir/Ritonavir Combination Therapy

The combination of atazanavir (ATV) and lopinavir/ritonavir (LPV/RTV) with nucleoside reverse transcriptase inhibitors (NRTI) has been used as a salvage regimen for human immunodeficiency virus (HIV)-positive patients. In this paper, we discuss two cases of HIV-positive patients who had long histories of virological failure following a heavy treatment of antiretroviral drugs, but then achieved virological suppression with double-boosted protease inhibitor (PI) regimens. In patients with multiple genotypic resistance to PIs and NRTIs, virological suppression can be achieved with a combination of ATV plus LPV/RTV with an NRTI backbone. The two cases in this report suggest that a combination of ATV plus LPV/RTV could be a useful salvage regimen for the subset of HIV-positive patients with limited treatment options.

Management of Antiviral-Resistant Chronic Hepatitis B Virus Infection / 대한소화기학회지

Substantial progress has been made in the treatment of chronic hepatitis B during the past decade. Nucleos(t)ide analogues are now widely used due to their convenience, less side effects, and considerable response rates. However, development of antiviral resistance is a major problem being considered as the most important factor for the treatment failure. Viral breakthrough associated with selection of antiviral-resistant hepatitis B virus (HBV) is usually followed by biochemical breakthrough, clinical deterioration, and even progressive liver failure. Therefore, appropriate management of antiviral resistance is critical for improving treatment outcomes. Strategies for the management of antiviral-resistant chronic HBV infection are described herein considering recently published guidelines. Lamivudine/telbivudine resistance can be managed by adding adefovir. Switching to adefovir or entecavir is also a viable option. However, careful follow-up of viral load is mandatory to detect any primary or secondary treatment failure in case of sequential monotherapy. Interferon or peg-interferon therapy can also be considered in case of young patients with compensated liver disease. For adefovir resistance, lamivudine can be added, but adding or switching to entecavir is a more reasonable option. Likewise, adding or switching to adefovir can be considered for entecavir resistance. Adding or switching to tenofovir needs to be considered upon availability. Experiences for clevudine resistance are still lacking, and need to be studied further upon the isolation of clinically resistant strains. To avoid emergence of resistant mutations, antiviral therapy should be initiated after careful balance of risk and benefit, and the most potent antiviral agent with the lowest resistance rate should be selected.

A five-year analysis of HBV mutations in a multidrug-resistant patient with chronic hepatitis B / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To investigate HBV mutations in reverse transcriptase (RT) gene and precore/basal core promoter (PC/BCP) regions in a chronic hepatitis B patient and to analyze the link between the mutations and drug resistance or HBeAg sero-conversion.</p><p><b>METHODS</b>Eighteen serum samples were collected from a chronic hepatitis B patient during his 14 hospitalizations from June 2002 to September 2007. HBV DNA was extracted and nested PCR was employed for amplification of target gene fragments. Direct sequencing of PCR products was performed followed by analysis with NTI software. The significance of the results was analyzed in combination with the clinical data of the patient.</p><p><b>RESULTS</b>Several mutations were identified in succession, including LAM-resistant mutations M204I/V and L180M+M204V, ETV-resistant mutation S202G, and HBeAg nonsense mutation G1896A. The results were in accordance with the disease progression of the patient.</p><p><b>CONCLUSION</b>Sequencing of HBV RT and PC/BCP regions is valuable for comprehensively checking the viral mutations and thus it is helpful in the surveillance of patients in clinics as a way for adopting reasonable antiviral therapy.</p>

Development of Clevudine Resistance after Switching from Lamivudine in a Patient with Chronic Hepatitis B / 대한소화기학회지

Clevudine is a nucleoside analog of the unnatural beta-L configuration which has potent antiviral activity against hepatitis B virus (HBV). Clevudine is expected to have similar pattern of resistance profile as lamivudine. However, there was no report on the mutation associated with clevudine resistance in patients with chronic hepatitis B. We report a case of young male patient with chronic hepatitis B who presented with clevudine resistance. The patient had received lamivudine therapy for 5 months with reduced serum HBV DNA levels. Then, lamivudine was switched to clevudine monotherapy. After the 6 months of clevudine therapy, the patient developed virologic breakthrough (>1.0x10(8) copies/mL) as well as biochemical breakthrough, which was associated with the presence of rtM204I plus rtL80I mutant. After switching from clevudine to adefovir, the viral load decreased with biochemical improvement.

Impact of the number of failed therapeutic regimes on the development of resistance mutations to HIV-1 in northeast Brazil

Highly-potent antiretroviral therapy is necessary to avoid viral replication in HIV patients; however, it can favor the appearance of resistance mutations. The mutations 41L, 67N, 70R, 210W, 215Y/F, 219E/Q, 44D and 118I are defined as nucleoside analogous mutations (NAMs), because they affect the efficacy of all nucleoside reverse transcriptase inhibitors (NRTI). The mutation most frequently associated with non-nucleoside reverse transcriptase inhibitors (NNRTIs) is 103N. 33W/F, 82A/F/L/T, 84V and 90M are called protease inhibitor resistance-associated mutations (PRAM), because they are associated with resistance to several protease inhibitors (PI). This study evaluated the development of resistance mutations and examine the susceptibility of HIV with these mutations to antiretrovirals in HIV-1 patients who have failed one or more therapy regimes. Analyses were made of 101 genotypic tests of patients with therapeutic failure to 2 or 3-drug regimens with NRTI, NNRTI or PI. We used the Stanford database to define the susceptibility profile of the viruses. The samples were divided into three treatment-failure groups: first (F), second (S) and multi-failure (MF) to antiretroviral regimens, and we correlated these groups with resistance profiles and principal mutations. There was a significant increase in resistance mutations V82A/F/L/T, I84V, L90M, M41L, K70R, L210W, T215Y/F and K219Q/E in MF. We also found significantly higher resistance to zidovudine, didanosine, stavudine and abacavir in MF. There was no increase in resistance to tenofovir (p=0.28) and lopinavir (p=0.079) in MF. A high degree of resistance to NNRTIs was observed in all groups. Increased resistance mutations will affect future therapeutic options for HIV patients in Brazil because it results in a significant increase in resistance to antiretroviral drugs.

Resistencia a la terapia antirretroviral en pacientes infectados con el virus VIH-1 en Chile 2002-2005 / Resistance to anti-retroviral therapy in Chilean patients with HIV-1 from 2002 to 2005

Background: Resistance limits the effectiveness of anti-retroviral therapy. In Chile, there is free access to highly active anti-retroviral therapy since 2001, but there is no information about the frequency of mutations associated to drug resistance. Aim: To determine the most common mutations associated to anti-retroviral drug resistance in Chile. Materials and Methods: Retrospective study of 710 genotype analysis coming from 568 patients aged 22 to 70 years (85 percent males) with virological failure. The analysis was performed using a commercially available sequencing kit (Trugene HIV-1 genotypic assay from Bayer S.A). Results: Mean CD4+ cell count and viral load were 154 cells/fil and 228784 RNA copies/ml, respectively. The frequency of resistance to nucleoside RT inhibitors (NRTI), non nucleoside RT inhibitors (NNRTI) and protease inhibitors (PI) was 71 percent, 62 percent and 22 percent, respectively. The most common mutations found were T215Y (46 percent), L10F (44 percent), Ml84V (3896), K103N (35 percent) and M41L (32 percent). Fifty five percent of mutations corresponded to the TAM (thymidine analogue mutations) group. Multiresistance was 47 percent to NNRTI, 7 percent to NRTI, 4 percent to PI and 0.7 percent to all groups. During the four years of the study, there was a significant increase in NNRTI resistance. Conclusions: These data provides important information about the epidemiology of drug resistance mutations and should help to design newHAARTstrategies.

Multi-drug resistant HIV-1 reverse transcriptase genotype in children treated with dual nucleoside reverse transcriptase inhibitors (NRTIs).

BACKGROUND: Multi-drug resistant HIV mutants have been reported after prolonged dual antiretroviral therapy. OBJECTIVE: To evaluate the prevalence and resistance pattern in HIV-infected children treated with dual NRTIs. MATERIAL AND METHOD: Records of HIV-infected children treated with dual NRTIs at Srinagarind Hospital, Khon Kaen University, Thailand, were reviewed for baseline data and their consensually-stored plasma were checked for the occurrence of HIV mutants by genotyping. RESULTS: Fifty-seven HIV-infected children were treated with dual NRTI regimens (27 males; 30 females). The median age and median CD4+ T-lymphocyte at genotypic testing were 83.5 months and 10.9%, respectively. The median duration of ARV therapy was 22 months. More than half the children (42) were on zidovudine and didanosine. A set of three or more nucleoside analog mutations (NAMs), conferring multi-dideoxynucleoside resistance, was found in 60% of the cases. CONCLUSION: High percentages of NAMs were found in HIV-infected children previously on dual ARV therapy for long periods. Genotypic testing was helpful in designing the second antiretroviral regimen.