Molecular characterization of rpoB gene mutations in isolates from tuberculosis patients in Cubal, Republic of Angola.

BACKGROUND: The importance of Mycobacterium tuberculosis strains with disputed rpoB mutations remains to be defined. This study aimed to assess the frequency and types of rpoB mutations in M. tuberculosis isolates from Cubal, Angola, a country with a high incidence of tuberculosis. METHODS: All isolates included (n = 308) were analyzed using phenotypic drug susceptibility testing and GenoType MTBDRplus assay. DNA sequencing of the rpoB gene and determination of rifampicin MIC by macrodilution method were additionally performed on isolates yielding discordant results (n = 12) and those in which the mutation detected was not characterized (n = 8). RESULTS: In total, 85.1% (74/87) of rifampicin-resistant strains had undisputed rpoB mutations -S450L (49), D435V (15), H445D (3), H445Y (2), Q432ins (1), L449M plus S450F (1), S450F (1), S450W (1) and S450Y (1)-; 10.3% (9/87) had disputed rpoB mutations-L430P plus S493L (1), N437del (1), H445L (3), D435Y (2), L452P (2)-, 2.3% (2.3%) showed no rpoB mutations and 2.3% (2/87) showed heteroresistance-D435Y plus L452P and L430P plus S493L-. CONCLUSION: Disputed rpoB mutations were common, occurring in 10.3% of rifampicin resistant isolates. Current phenotyping techniques may be unable to detect this resistance pattern. To increase their sensitivity, a lower concentration of RIF could be used in these tests or alternatively, rpoB mutations could be screened and characterized in all M. tuberculosis strains.

Utility of the Cobas® Plasma Separation Card as a Sample Collection Device for Serological and Virological Diagnosis of Hepatitis C Virus Infection.

Diagnosis and clinical management of people infected with hepatitis C virus (HCV) relies on results from a combination of serological and virological tests. The aim of this study was to compare the performance of dried plasma spots (DPS), prepared using the cobas® Plasma Separation Card (PSC), to plasma and serum from venipuncture, for HCV diagnosis. We carried out a prospective study using DPS and paired plasma or serum samples. Serum and DPS samples were analyzed by immunoassay using Elecsys® Anti-HCV II (Roche). Plasma and DPS samples were analyzed using the cobas® HCV viral load and cobas® HCV genotyping tests (Roche). All DPS samples that had high anti-HCV antibody titers in serum were also antibody-positive, as were five of eight samples with moderate titers. Eight samples with low titers in serum were negative with DPS. Among 80 samples with plasma HCV viral loads between 61.5 and 2.2 × 108 IU/mL, 74 were RNA-positive in DPS. The mean viral load difference between plasma and DPS was 2.65 log10 IU/mL. The performance of DPS for detection of serological and virological markers of hepatitis C virus infection was comparable to that of the conventional specimen types. However, the limits of detection were higher for DPS.

Diagnóstico microbiológico de las infecciones virales respiratorias en el paciente adulto / Microbiological diagnosis of viral respiratory infections in the adult patient

Las técnicas tradicionales para el diagnóstico de los virus respiratorios siguen estando todavía vigentes, aunque los métodos moleculares aplicados al diagnóstico de la infección viral respiratoria han supuesto una auténtica revolución. Las técnicas moleculares tienen como principales ventajas una excelente sensibilidad, especificidad, capacidad de adaptación a virus emergentes, capacidad para detectar múltiples dianas en un mismo ensayo y posibilidad de automatización. Adicionalmente, estas técnicas han permitido profundizar en el papel de los virus en la infección respiratoria aguda a la vez que han descrito la existencia de nuevos virus no conocidos previamente. Los métodos moleculares y no moleculares de diagnóstico rápido para 1 o más virus respiratorios han permitido la toma de decisiones de forma inmediata en el manejo del paciente mejorando su pronóstico y evitando la transmisión nosocomial. Sin embargo, también hay inconvenientes, la mayor sensibilidad de las técnicas moleculares ha supuesto un incremento significativo de la tasa de codetecciones múltiples de virus respiratorios, cuya implicación clínica resulta difícil de interpretar. Finalmente queda por demostrar todavía si la utilización de las nuevas técnicas, de elevado coste, en el diagnóstico microbiológico de rutina de las infecciones respiratorias agudas de etiología viral, en el paciente hospitalizado, es coste-efectiva

Conventional techniques for the diagnosis of respiratory viruses are still being used, although molecular methods are now considered as a gold standard in this field. Molecular techniques have a great number of advantages such as an excellent sensitivity, specificity, adaptability to emerging viruses, capability for multiplex and for automation. With all the available repertoire of techniques for microbiological diagnosis, the knowledge relative to respiratory viruses is growing up not only for new aetiological agents but also for its epidemiology. The advances in molecular and non-molecular fast diagnostic methods for one or more respiratory viruses allow quick decisions in the management of the patient. However, there are also disadvantages. The great sensitivity of molecular techniques has meant a significant increase in the rate of multiple detections of respiratory viruses, whose clinical involvement is difficult to interpret. Finally, it remains to show whether the use of new techniques, of high cost, in the microbiological routine diagnosis of acute respiratory viral infections in the hospitalized patient, is cost effective

Diagnóstico microbiológico de las infecciones virales respiratorias en el paciente adulto / Microbiological diagnosis of viral respiratory infections in the adult patient

Las técnicas tradicionales para el diagnóstico de los virus respiratorios siguen estando todavía vigentes, aunque los métodos moleculares aplicados al diagnóstico de la infección viral respiratoria han supuesto una auténtica revolución. Las técnicas moleculares tienen como principales ventajas una excelente sensibilidad, especificidad, capacidad de adaptación a virus emergentes, capacidad para detectar múltiples dianas en un mismo ensayo y posibilidad de automatización. Adicionalmente, estas técnicas han permitido profundizar en el papel de los virus en la infección respiratoria aguda a la vez que han descrito la existencia de nuevos virus no conocidos previamente. Los métodos moleculares y no moleculares de diagnóstico rápido para 1 o más virus respiratorios han permitido la toma de decisiones de forma inmediata en el manejo del paciente mejorando su pronóstico y evitando la transmisión nosocomial. Sin embargo, también hay inconvenientes, la mayor sensibilidad de las técnicas moleculares ha supuesto un incremento significativo de la tasa de codetecciones múltiples de virus respiratorios, cuya implicación clínica resulta difícil de interpretar. Finalmente queda por demostrar todavía si la utilización de las nuevas técnicas, de elevado coste, en el diagnóstico microbiológico de rutina de las infecciones respiratorias agudas de etiología viral, en el paciente hospitalizado, es coste-efectiva (AU)

Conventional techniques for the diagnosis of respiratory viruses are still being used, although molecular methods are now considered as a gold standard in this field. Molecular techniques have a great number of advantages such as an excellent sensitivity, specificity, adaptability to emerging viruses, capability for multiplex and for automation. With all the available repertoire of techniques for microbiological diagnosis, the knowledge relative to respiratory viruses is growing up not only for new aetiological agents but also for its epidemiology. The advances in molecular and non-molecular fast diagnostic methods for one or more respiratory viruses allow quick decisions in the management of the patient. However, there are also disadvantages. The great sensitivity of molecular techniques has meant a significant increase in the rate of multiple detections of respiratory viruses, whose clinical involvement is difficult to interpret. Finally, it remains to show whether the use of new techniques, of high cost, in the microbiological routine diagnosis of acute respiratory viral infections in the hospitalized patient, is cost effective (AU)

Metaneumovirus humano / Human metapneumovirus

No disponible

[Prevalence of Chlamydia trachomatis infection, as evaluated by molecular biology methods]. / Prevalencia de infección por Chlamydia trachomatis determinada mediante métodos de biología molecular.

BACKGROUND: To determine the prevalence of Chlamydia trachomatis infection in our area by molecular methods. METHODS: We describe the combined results of three studies carried out in the city of Barcelona including a total of 408 women considered to be at high risk for acquiring a sexually transmitted disease (STD). The first study was performed in 94 women attended at a public STD clinic located downtown, the second in 112 women attended at the Hospital Clinic and the third in 202 women attended at Hospital Vall d'Hebron (both third-level hospitals). In the first and third study endocervical exudate was tested with a PCR technique, and in the second study LCR was performed in 20-ml urine samples. RESULTS: Chlamydia trachomatis was detected in 1 woman in the first study, in no women in the second and in 3 women in the third. The prevalence of Chlamydia trachomatis infection detected in the three studies using molecular biology techniques was 1.06%, 0% and 1.48% respectively, giving an overall prevalence of 0.98%. CONCLUSION: The prevalence of Chlamydia trachomatis infection in our geographic area is surprisingly low.

Prevalencia de infección por Chlamydia trachomatis determinada mediante métodos de biología molecular / Prevalence of Chlamydia trachomatis infection, as evaluated by molecular biology methods

FUNDAMENTO. Determinar la prevalencia de la infección por Chlamydia trachomatis por métodos moleculares. MÉTODOS. Se describen conjuntamente los resultados de 3 trabajos realizados en la ciudad de Barcelona y en los que se estudiaron 408 mujeres consideradas como de alto riesgo para la adquisición de una enfermedad de transmisión sexual (ETS). El primer estudio incluyó a 94 mujeres atendidas en un centro público de ETS, el segundo a 112 mujeres atendidas en el Hospital Clínico y el tercero a 202 mujeres atendidas en el Hospital Vall d'Hebron de Barcelona. En el primer y tercer estudio se practicó toma endocervical y se realizó una técnica de reacción en cadena de la polimerasa (PCR). En el segundo se realizó reacción en cadena de la ligasa (LCR) a partir del primer chorro de orina. RESULTADOS. Chlamydia trachomatis se detectó en una sola paciente en el primer estudio, en ninguna en el segundo y en 3 pacientes en el tercero. Es decir que utilizando técnicas de biología molecular las prevalencias de infección por Chlamydia trachomatis fueron del 1,06, 0 y 1,48 por ciento, respectivamente, siendo la prevalencia total del 0,98 por ciento. CONCLUSIONES. La prevalencia de la infección por Chlamydia trachomatis en nuestra área geográfica es sorprendentemente baja (AU)