RESUMEN

Whole Genome Sequencing (WGS) is a promising tool in the global fight against tuberculosis (TB). The aim of this study was to evaluate the use of WGS in routine conditions for detection of drug resistance markers and transmission clusters in a multidrug-resistant TB hot-spot area in Peru. For this, 140 drug-resistant Mycobacterium tuberculosis strains from Lima and Callao were prospectively selected and processed through routine (GenoType MTBDRsl and BACTEC MGIT) and WGS workflows, simultaneously. Resistance was determined in accordance with the World Health Organization mutation catalogue. Agreements between WGS and BACTEC results were calculated for rifampicin, isoniazid, pyrazinamide, moxifloxacin, levofloxacin, amikacin and capreomycin. Transmission clusters were determined using different cut-off values of Single Nucleotide Polymorphism differences. 100% (140/140) of strains had valid WGS results for 13 anti-TB drugs. However, the availability of final, definitive phenotypic BACTEC MGIT results varied by drug with 10-17% of invalid results for the seven compared drugs. The median time to obtain results of WGS for the complete set of drugs was 11.5 days, compared to 28.6-52.6 days for the routine workflow. Overall categorical agreement by WGS and BACTEC MGIT for the compared drugs was 96.5%. Kappa index was good (0.65≤k≤1.00), except for moxifloxacin, but the sensitivity and specificity values were high for all cases. 97.9% (137/140) of strains were characterized with only one sublineage (134 belonging to "lineage 4" and 3 to "lineage 2"), and 2.1% (3/140) were mixed strains presenting two different sublineages. Clustering rates of 3.6% (5/140), 17.9% (25/140) and 22.1% (31/140) were obtained for 5, 10 and 12 SNP cut-off values, respectively. In conclusion, routine WGS has a high diagnostic accuracy to detect resistance against key current anti-TB drugs, allowing results to be obtained through a single analysis and helping to cut quickly the chain of transmission of drug-resistant TB in Peru.

Asunto(s)

RESUMEN

The present study assessed the diagnostic performance of the Xpert®Xpress SARS-CoV-2 test in comparison with the Charité protocol real-time RT PCR for the detection of SARS-CoV-2 in Peruvian patients. This was a diagnostic test study that included 100 nasal and pharyngeal swab samples. We obtained an overall concordance of 98.70% (95%CI: 92.98-99.97), with a kappa coefficient of 0.97 (95%CI: 0.86-1.00) and sensitivity and relative specificity rates of 100% and 96.15%, respectively. Additionally, the percentage of the area under the ROC curve was 98.08% in both cases, and an analytical specificity rate of 100% was obtained for the different respiratory viruses evaluated. In conclusion, the Xpert®Xpress SARS-CoV-2 test, by using nasal and pharyngeal swab samples, was highly sensitive and specific, and the kappa coefficient showed an excellent correlation when compared to the reference test. Motivation for the study. To describe and evaluate a closed molecular platform, easy to use and of importance in Peru for the management of diseases of public health priority, now implemented for the detection of SARS-CoV-2. Main findings. Highly sensitive and specific molecular test, with excellent correlation compared to the reference test for detecting SARS-CoV-2. Implications. Can be used in point-of-care laboratories for rapid molecular detection of different infectious agents, including SARS-CoV-2. Little expertise and minimal infrastructure are required to implement it.

En el presente estudio se estimó el rendimiento diagnóstico de la prueba Xpert®Xpress SARS-CoV-2 en comparación con la RT PCR en tiempo real-protocolo Charité, para la detección de SARS-CoV-2 en pacientes peruanos. Se trató de un diseño de prueba diagnóstica que incluyó 100 muestras de hisopado nasal y faríngeo. Se obtuvo una concordancia global de 98,70% (IC95%: 92,98-99,97), con un coeficiente kappa de 0,97 (IC95%: 0,86-1.00); se estimó una sensibilidad y especificad relativa de 100% y 96,15%, respectivamente. Adicionalmente, el porcentaje del área bajo la curva ROC fue 98,08% en ambos casos y se obtuvo una especificidad analítica del 100% para los diferentes virus respiratorios evaluados. En conclusión, la prueba Xpert®Xpress SARS-CoV-2 a partir de muestras de hisopado nasal y faríngeo fue altamente sensible y específica, así mismo el coeficiente kappa mostró una excelente correlación, al compararla con la prueba de referencia. Motivación para realizar el estudio. Descripción y evaluación de una plataforma molecular cerrada, de fácil uso y de importancia en el Perú para el manejo de enfermedades de prioridad en salud pública, ahora implementada para la detección de SARS-CoV-2. Principales hallazgos. Prueba molecular altamente sensible y específica, con una correlación excelente con respecto al referente para detectar SARS-CoV-2. Implicancias. Puede ser utilizada en los laboratorios que se encuentran en los puntos de atención del paciente para la detección molecular rápida de diferentes agentes infecciosos, incluido el SARS-CoV-2. Se necesita poca experticia y mínima infraestructura para poder implementarla.

Asunto(s)

RESUMEN

RESUMEN En el presente estudio se estimó el rendimiento diagnóstico de la prueba Xpert®Xpress SARS-CoV-2 en comparación con la RT PCR en tiempo real-protocolo Charité, para la detección de SARS-CoV-2 en pacientes peruanos. Se trató de un diseño de prueba diagnóstica que incluyó 100 muestras de hisopado nasal y faríngeo. Se obtuvo una concordancia global de 98,70% (IC95%: 92,98-99,97), con un coeficiente kappa de 0,97 (IC95%: 0,86-1.00); se estimó una sensibilidad y especificad relativa de 100% y 96,15%, respectivamente. Adicionalmente, el porcentaje del área bajo la curva ROC fue 98,08% en ambos casos y se obtuvo una especificidad analítica del 100% para los diferentes virus respiratorios evaluados. En conclusión, la prueba Xpert®Xpress SARS-CoV-2 a partir de muestras de hisopado nasal y faríngeo fue altamente sensible y específica, así mismo el coeficiente kappa mostró una excelente correlación, al compararla con la prueba de referencia.

ABSTRACT The present study assessed the diagnostic performance of the Xpert®Xpress SARS-CoV-2 test in comparison with the Charité protocol real-time RT PCR for the detection of SARS-CoV-2 in Peruvian patients. This was a diagnostic test study that included 100 nasal and pharyngeal swab samples. We obtained an overall concordance of 98.70% (95%CI: 92.98-99.97), with a kappa coefficient of 0.97 (95%CI: 0.86-1.00) and sensitivity and relative specificity rates of 100% and 96.15%, respectively. Additionally, the percentage of the area under the ROC curve was 98.08% in both cases, and an analytical specificity rate of 100% was obtained for the different respiratory viruses evaluated. In conclusion, the Xpert®Xpress SARS-CoV-2 test, by using nasal and pharyngeal swab samples, was highly sensitive and specific, and the kappa coefficient showed an excellent correlation when compared to the reference test.

Asunto(s)

RESUMEN

Objetivos. Determinar el rendimiento diagnóstico de la prueba rápida SD dengue DUO (Inyecta) para la detección de NS1, IgM e IgG en comparación con la prueba de ELISA. Materiales y métodos. Es una evaluación de prueba diagnóstica que incluyó 286 muestras de suero de pacientes con sintomatología atribuible a dengue de zonas endémicas del Perú. Las muestras se analizaron por ELISA y la prueba rápida SD dengue DUO (Inyecta) para IgM, NS1 e IgG en el Instituto de Investigación Nutricional en Lima. Resultados. La sensibilidad de la prueba rápida fue de 68% para NS1 e IgM, y 86% para IgG, mejorando este parámetro a 75% y 81% para NS1 e IgM, respectivamente, en los tres primeros días. La especificidad para los tres analitos fue mayor a 87%. La concordancia de los resultados obtenidos medidos por el coeficiente Kappa para los tres analitos fue buena y no se encontró reacción cruzada con otros arbovirus. Conclusiones. La prueba rápida SD Dengue DUO permite detectar con una adecuada sensibilidad y especificidad NS1, IgM e IgG. La sensibilidad para IgM y NS1 aumenta cuando se detecta en los tres primeros días de síntomas, por lo que se recomienda su implementación en los centros de primer nivel de atención para un diagnóstico temprano y oportuno.

Objectives . To assess the diagnostic performance of the SD dengue DUO rapid test (Inyecta) for the detection of NS1, IgM and IgG in comparison to the ELISA test. Materials and methods . This is a diagnostic test evaluation that included 286 serum samples from patients with symptomatology attributable to dengue from endemic areas of Peru. The samples were analyzed by ELISA and the SD dengue DUO rapid test (Inyecta) for IgM, NS1 and IgG at the Instituto de Investigación Nutricional in Lima. Results . The sensitivity of the rapid test was 68.0% for NS1 and IgM, and 86.0% for IgG, improving to 75.0% and 81.0% for NS1 and IgM, respectively, during the first three days. The specificity for all three analytes was greater than 87.0%. The concordance of the results, measured by the Kappa coefficient for the three analytes, was good and no cross-reaction with other arboviruses was found. Conclusions . The SD dengue DUO rapid test allows detection of NS1, IgM and IgG with adequate sensitivity and specificity. Sensitivity for IgM and NS1 increases when detected during the first three days of symptoms. Therefore, we recommend its implementation in primary care centers for early and timely diagnosis.

Asunto(s)

RESUMEN

BACKGROUND: Tuberculosis (TB) is a communicable, preventable and curable disease caused by the bacterium Mycobacterium tuberculosis (MTB). Peru is amongst the 30 countries with the highest burden of multidrug-resistant tuberculosis (MDR-TB) worldwide. In the fight against drug-resistant tuberculosis, the UKMYC6 microdilution plate was developed and validated by the CRyPTIC project. The objective of the study was to evaluate the use of the broth microdilution (BMD) plate methodology for susceptibility testing of drug-resistant MTB strains in Peru. METHODS: MTB strains isolated between 2015 and 2018 in Peru were used. 496 nationally-representative strains determined as drug-resistant by the routine 7H10 Agar Proportion Method (APM) were included in the present study. The Minimum Inhibitory Concentration (MIC) of 13 antituberculosis drugs were determined for each strain using the UKMYC6 microdilution plates. Diagnostic agreement between APM and BMD plate methodology was determined for rifampicin, isoniazid, ethambutol, ethionamide, kanamycin and levofloxacin. Phenotypes were set using binary (or ternary) classification based on Epidemiological cut-off values (ECOFF/ECV) proposed by the CRyPTIC project. Whole Genome Sequencing (WGS) was performed on strains with discrepant results between both methods. RESULTS: MIC distributions were determined for 13 first- and second-line anti-TB drugs, including new (bedaquiline, delamanid) and repurposed (clofazimine, linezolid) agents. MIC results were available for 80% (397/496) of the strains at 14 days and the remainder at 21 days. The comparative analysis determined a good agreement (0.64 ≤ k ≤ 0.79) for the drugs rifampicin, ethambutol, ethionamide and kanamycin, and the best agreement (k > 0.8) for isoniazid and levofloxacin. Overall, 12% of MIC values were above the UKMYC6 plate dilution ranges, most notably for the drugs rifampicin and rifabutin. No strain presented MICs higher than the ECOFF/ECV values for the new or repurposed drugs. Discrepant analysis using genotypic susceptibility testing by WGS supported half of the results obtained by APM (52%, 93/179) and half of those obtained by BMD plate methodology (48%, 86/179). CONCLUSIONS: The BMD methodology using the UKMYC6 plate allows the complete susceptibility characterization, through the determination of MICs, of drug-resistant MTB strains in Peru. This methodology shows good diagnostic performances for rifampicin, isoniazid, ethambutol, ethionamide, kanamycin and levofloxacin. It also allows for the characterization of MICs for other drugs used in previous years against tuberculosis, as well as for new and repurposed drugs recently introduced worldwide.

Asunto(s)

RESUMEN

BACKGROUND: Oropouche fever is an infectious disease caused by the Oropouche virus (OROV). The diagnosis and prediction of the clinical picture continue to be a great challenge for clinicians who manage patients with acute febrile syndrome. Several symptoms have been associated with OROV virus infection in patients with febrile syndrome; however, to date, there is no clinical prediction rule, which is a fundamental tool to help the approach of this infectious disease. OBJECTIVE: To assess the performance of a prediction model based solely on signs and symptoms to diagnose Oropouche virus infection in patients with acute febrile syndrome. MATERIALS AND METHODS: Validation study, which included 923 patients with acute febrile syndrome registered in the Epidemiological Surveillance database of three arbovirus endemic areas in Peru. RESULTS: A total of 97 patients (19%) were positive for OROV infection in the development group and 23.6% in the validation group. The area under the curve was 0.65 and the sensitivity, specificity, PPV, NPV, LR + and LR- were 78.2%, 35.1%, 27.6%, 83.6%, 1.20 and 0.62, respectively. CONCLUSIONS: The development of a clinical prediction model for the diagnosis of Oropouche based solely on signs and symptoms does not work well. This may be due to the fact that the symptoms are nonspecific and related to other arbovirus infections, which confuse and make it difficult to predict the diagnosis, especially in endemic areas of co-infection of these diseases. For this reason, epidemiological surveillance of OROV in various settings using laboratory tests such as PCR is important.

Asunto(s)

RESUMEN

OBJECTIVES: Motivation for the study: search for accessible and efficient new diagnostic alternatives for the detection of the disease caused by the dengue virus. Main findings: good efficiency of the rapid test during the first days of the disease. As well as its high power to discriminate against other similar mosquito-borne diseases such as Zika and Oropuche. Implications: it could be applied as a screening test in endemic regions that do not have equipment or trained personnel to perform sophisticated and/or complex diagnostic tests. Strengthening public health policies in epidemiological surveillance, early diagnosis and timely treatment. To assess the diagnostic performance of the SD dengue DUO rapid test (Inyecta) for the detection of NS1, IgM and IgG in comparison to the ELISA test. MATERIALS AND METHODS: . This is a diagnostic test evaluation that included 286 serum samples from patients with symptomatology attributable to dengue from endemic areas of Peru. The samples were analyzed by ELISA and the SD dengue DUO rapid test (Inyecta) for IgM, NS1 and IgG at the Instituto de Investigación Nutricional in Lima. RESULTS: . The sensitivity of the rapid test was 68.0% for NS1 and IgM, and 86.0% for IgG, improving to 75.0% and 81.0% for NS1 and IgM, respectively, during the first three days. The specificity for all three analytes was greater than 87.0%. The concordance of the results, measured by the Kappa coefficient for the three analytes, was good and no cross-reaction with other arboviruses was found. CONCLUSIONS: . The SD dengue DUO rapid test allows detection of NS1, IgM and IgG with adequate sensitivity and specificity. Sensitivity for IgM and NS1 increases when detected during the first three days of symptoms. Therefore, we recommend its implementation in primary care centers for early and timely diagnosis.

OBJETIVOS.: Motivación para realizar el estudio: búsqueda de nuevas alternativas diagnósticas de fácil acceso y manejo eficientes para la detección de la enfermedad causada por el virus del dengue. Principales hallazgos: buena eficiencia de la prueba rápida evaluada en los primeros días de la enfermedad. Así como su alto poder para discriminar frente a otras enfermedades similares transmitidas por mosquitos como el Zika y Oropuche. Implicancias: podría aplicarse como una prueba de tamizaje en regiones endémicas que no cuentan con equipo o personal capacitado para realizar pruebas diagnósticas sofisticadas y/o complejas al momento de captar al paciente. Fortaleciendo las políticas de salud pública en vigilancia epidemiológica, diagnóstico temprano y tratamiento oportuno. Determinar el rendimiento diagnóstico de la prueba rápida SD dengue DUO (Inyecta) para la detección de NS1, IgM e IgG en comparación con la prueba de ELISA. MATERIALES Y MÉTODOS.: Es una evaluación de prueba diagnóstica que incluyó 286 muestras de suero de pacientes con sintomatología atribuible a dengue de zonas endémicas del Perú. Las muestras se analizaron por ELISA y la prueba rápida SD dengue DUO (Inyecta) para IgM, NS1 e IgG en el Instituto de Investigación Nutricional en Lima. RESULTADOS.: La sensibilidad de la prueba rápida fue de 68% para NS1 e IgM, y 86% para IgG, mejorando este parámetro a 75% y 81% para NS1 e IgM, respectivamente, en los tres primeros días. La especificidad para los tres analitos fue mayor a 87%. La concordancia de los resultados obtenidos medidos por el coeficiente Kappa para los tres analitos fue buena y no se encontró reacción cruzada con otros arbovirus. CONCLUSIONES.: La prueba rápida SD Dengue DUO permite detectar con una adecuada sensibilidad y especificidad NS1, IgM e IgG. La sensibilidad para IgM y NS1 aumenta cuando se detecta en los tres primeros días de síntomas, por lo que se recomienda su implementación en los centros de primer nivel de atención para un diagnóstico temprano y oportuno.

Asunto(s)

RESUMEN

Peru has the highest burden of multidrug-resistant tuberculosis in the Americas region. Since 1999, the annual number of extensively drug-resistant tuberculosis (XDR-TB) Peruvian cases has been increasing, becoming a public health challenge. The objective of this study was to perform genomic characterization of Mycobacterium tuberculosis strains obtained from Peruvian patients with XDR-TB diagnosed from 2011 to 2015 in Peru. Whole genome sequencing (WGS) was performed on 68 XDR-TB strains from different regions of Peru. 58 (85.3%) strains came from the most populated districts of Lima and Callao. Concerning the lineages, 62 (91.2%) strains belonged to the Euro-American Lineage, while the remaining 6 (8.8%) strains belonged to the East-Asian Lineage. Most strains (90%) had high-confidence resistance mutations according to pre-established WHO-confident grading system. Discordant results between microbiological and molecular methodologies were caused by mutations outside the hotspot regions analysed by commercial molecular assays (rpoB I491F and inhA S94A). Cluster analysis using a cut-off ≤ 10 SNPs revealed that only 23 (34%) strains evidenced recent transmission links. This study highlights the relevance and utility of WGS as a high-resolution approach to predict drug resistance, analyse transmission of strains between groups, and determine evolutionary patterns of circulating XDR-TB strains in the country.

Asunto(s)

RESUMEN

OBJECTIVE.: To determine the genetic structure of drug-resistant strains of Mycobacterium tuberculosis that circulated throughout Peru during the years 2011-2015, by using haplotypes obtained from a line probe assay. MATERIALS AND METHODS.: A total of 6589 samples that were admitted to the Instituto Nacional de Salud for routine diagnosis using the GenoType® MTBDRplus v2 assay were analyzed during the study period. Resistant haplotypes were created by concatenating 21 polymorphic sites of the evaluated genes using the line probe assay; and the association analysis was carried out with phenotypes obtained by the 7H10 agar ratio method. RESULTS.: The most frequent mutations were: rpoB S531L (55.4%) and rpoB D516V (18.5%) for rifampicin resistance, and katG S315T (59.5%) and inhA c-15t (25.7%) for isoniazid resistance. We obtained 13 representative haplotypes (87.8% of analyzed samples), 6 corresponded to the multidrug-resistant genotype, 4 to the isoniazid mono-resistant genotype and 3 to the rifampicin mono-resistant genotype. Eighteen regions and the province of Callao showed high haplotype diversity; four showed moderate diversity and two showed low diversity. CONCLUSIONS.: Most regions showed high haplotype diversity; in addition, most drug-resistant strains of Mycobacterium tuberculosis were concentrated in the cities of Lima and Callao. Likewise, drug-resistant Mycobacterium tuberculosis strains circulating in Peru mainly contain the genetic markers with the highest prevalence worldwide, which are associated with resistance to rifampicin and isoniazid.

OBJETIVO.: Determinar la estructura genética de las cepas drogorresistentes de Mycobacterium tuberculosis que circularon en todo el Perú durante los años 2011-2015 a través de haplotipos obtenidos de un ensayo con sondas en línea. MATERIALES Y MÉTODOS.: Se analizaron 6589 muestras que ingresaron al Instituto Nacional de Salud para el diagnóstico rutinario mediante el ensayo GenoType® MTBDRplus v2, durante el periodo de estudio. Se crearon haplotipos resistentes mediante la concatenación de 21 sitios polimórficos de los genes evaluados por el ensayo con sondas en línea, y se realizó el análisis de asociación con fenotipos obtenidos por el método de proporciones agar 7H10. RESULTADOS.: Las mutaciones de mayores frecuencias fueron: rpoB S531L (55,4%) y rpoB D516V (18,5%) para la resistencia a rifampicina, y katG S315T (59,5%) e inhA c-15t (25,7%) para la resistencia a isoniacida. Se obtuvieron 13 haplotipos representativos (87,8% de muestras analizadas) de los cuales seis correspondieron al genotipo multidrogorresistente, cuatro al genotipo monorresistente a isoniacida y tres al genotipo monorresistente a rifampicina. Dieciocho departamentos, y la provincia del Callao, presentaron una alta diversidad haplotípica; cuatro presentaron moderada diversidad y dos presentaron baja diversidad. CONCLUSIONES.: Existe una alta diversidad haplotípica en la mayoría de los departamentos, además de una concentración de las cepas de Mycobacterium tuberculosis drogorresistentes en las ciudades de Lima y Callao. Asimismo, las cepas de Mycobacterium tuberculosis con perfil drogorresistente que circulan en el Perú contienen principalmente los marcadores genéticos de mayor prevalencia a nivel mundial asociados con la resistencia frente a rifampicina e isoniacida.

Asunto(s)

RESUMEN

BACKGROUND: Acute infective gastroenteritis (AIG) is a leading cause of mortality in children worldwide. In Peru, more than 40% of cases of AIG occurring in children under 5 years old. The disruption of the gut microbiota can increase risk for several health complications especially in patients with gastric infections caused by viruses or bacteria. OBJECTIVE: The main objective of this study was to describe the prevalence of 13 representative bacteria from the gut microbiota (GM) in stools samples from children under 5 years of age with acute infective gastroenteritis. RESULTS: The most commonly isolated bacteria from the GM were Firmicutes (63.2% 74/117) Bacteriodetes (62.4%; 73/117), Lactobacillus (59.8%; 70/117), Prevotella (57.2%; 67/117), Proteobacterium (53.8%; 63/117), regardless of the etiological agent responsible for the AIG. Interestingly, despite the high prevalence of Firmicutes, Bacteroidetes, Lactobacillus and Prevotella across all samples, a visible reduction of these agents was observed especially among patients with a single bacterial infection or even bacteria-bacteria coinfections when compared to viral etiologies. Patients with exclusive or mixed breastfeeding registered the highest amount of gut microbiota bacteria, in contrast to infants who received formula or were not breastfed.

Asunto(s)

Asunto(s)

RESUMEN

RESUMEN Objetivos. Sistematizar la información disponible referente a las mutaciones que confieren resistencia a los fármacos antituberculosis de primera línea. Materiales y métodos. Se realizó una revisión sistemática de la literatura científica para identificar artículos que reportaron mutaciones que confieren resistencia a fármacos antituberculosis de primera línea. Esta búsqueda hizo énfasis en la resistencia a los fármacos de isoniazida y rifampicina en cepas de M. tuberculosis de pacientes peruanos. La búsqueda fue realizada en PubMed y LILACS (Literatura Latinoamericana y del Caribe en Ciencias de la Salud). Resultados. Se incluyeron 14 artículos de los cuales tres reportaron mutaciones asociadas con resistencia a isoniazida, seis a rifampicina, ocho a pirazinamida y uno a etambutol. Todas las mutaciones a isoniazida o rifampicina fueron identificadas directa o indirectamente mediante la prueba de diagnóstico molecular GenoType MTBDRplus® v2.0. La mayor variabilidad de mutaciones fue determinada en la resistencia a pirazinamida. Conclusiones. Existe una gran variabilidad de mutaciones asociadas con resistencia a fármacos antituberculosis que han sido reportadas en Perú, y se sistematizan en el presente reporte. Estas mutaciones deben de ser tomadas en cuenta para el desarrollo de dispositivos diagnósticos o selección de pruebas diagnósticas a ser aplicadas en nuestro país.

ABSTRACT Objective. To systematize available information regarding mutations that confer resistance to first-line anti-tuberculosis drugs. Materials and Methods. A systematic review of the scientific literature was conducted to identify articles that reported mutations conferring resistance to first-line anti-tuberculosis drugs. This search emphasized resistance to isoniazid and rifampicin drugs in M. tuberculosis strains of Peruvian patients. The search was performed on PubMed and LILACS (Latin American and Caribbean Health Sciences Literature). Results. Fourteen (14) articles were included, of which three reported mutations associated with resistance to isoniazid, six to rifampicin, eight to pyrazinamide and one to ethambutol. All mutations to isoniazid or rifampicin were identified directly or indirectly by the molecular diagnostic test GenoType MTBDRplus® v2.0. The greatest variability of mutations was determined in resistance to pyrazinamide. Conclusions. There is a great variability of mutations associated with resistance to anti-tuberculosis drugs that have been reported in Peru, and they are systematized in this report. These mutations must be taken into account for the development of diagnostic devices or selection of diagnostic tests to be applied in our country.

Asunto(s)

RESUMEN

OBJECTIVE.: To systematize available information regarding mutations that confer resistance to first-line anti-tuberculosis drugs. MATERIALS AND METHODS.: A systematic review of the scientific literature was conducted to identify articles that reported mutations conferring resistance to first-line anti-tuberculosis drugs. This search emphasized resistance to isoniazid and rifampicin drugs in M. tuberculosis strains of Peruvian patients. The search was performed on PubMed and LILACS (Latin American and Caribbean Health Sciences Literature). RESULTS.: Fourteen (14) articles were included, of which three reported mutations associated with resistance to isoniazid, six to rifampicin, eight to pyrazinamide and one to ethambutol. All mutations to isoniazid or rifampicin were identified directly or indirectly by the molecular diagnostic test GenoType MTBDRplus® v2.0. The greatest variability of mutations was determined in resistance to pyrazinamide. CONCLUSIONS.: There is a great variability of mutations associated with resistance to anti-tuberculosis drugs that have been reported in Peru, and they are systematized in this report. These mutations must be taken into account for the development of diagnostic devices or selection of diagnostic tests to be applied in our country.

OBJETIVOS.: Sistematizar la información disponible referente a las mutaciones que confieren resistencia a los fármacos antituberculosis de primera línea. MATERIALES Y MÉTODOS.: Se realizó una revisión sistemática de la literatura científica para identificar artículos que reportaron mutaciones que confieren resistencia a fármacos antituberculosis de primera línea. Esta búsqueda hizo énfasis en la resistencia a los fármacos de isoniazida y rifampicina en cepas de M. tuberculosis de pacientes peruanos. La búsqueda fue realizada en PubMed y LILACS (Literatura Latinoamericana y del Caribe en Ciencias de la Salud). RESULTADOS.: Se incluyeron 14 artículos de los cuales tres reportaron mutaciones asociadas con resistencia a isoniazida, seis a rifampicina, ocho a pirazinamida y uno a etambutol. Todas las mutaciones a isoniazida o rifampicina fueron identificadas directa o indirectamente mediante la prueba de diagnóstico molecular GenoType MTBDRplus® v2.0. La mayor variabilidad de mutaciones fue determinada en la resistencia a pirazinamida. CONCLUSIONES.: Existe una gran variabilidad de mutaciones asociadas con resistencia a fármacos antituberculosis que han sido reportadas en Perú, y se sistematizan en el presente reporte. Estas mutaciones deben de ser tomadas en cuenta para el desarrollo de dispositivos diagnósticos o selección de pruebas diagnósticas a ser aplicadas en nuestro país.

Asunto(s)

RESUMEN

Objective To determine the use and performance of a line probe assay (LPA) compared with conventional culture and drug sensitivity testing (CDST) in patients registered with tuberculosis (TB) under routine program conditions in Peru in 2011-2013. Methods This was a descriptive, operational research, cross-sectional study of sputum specimens from patients with smear-positive pulmonary TB and mycobacterial cultures from patients with smear-negative or positive TB. Drug resistance to rifampicin and/or isoniazid detected by LPA was compared to CDST. Sensitivity, specificity, and predictive values were calculated and reliability for detecting drug resistance was assessed through kappa coefficient, with values 0.61-0.80 showing substantial correlation, and 0.81 or above showing almost-perfect correlation. Results In 2011-2013, there were 16 169 LPA tests performed, with the proportion of TB patients receiving the test increasing from 3.2% to 30.2%. In all, 2 905 LPA test results were compared to CDST. For LPA in sputum specimens, sensitivity for rifampicin was 92%; isoniazid, 94%; and MDR-TB, 88%; while specificity for rifampicin was 92%; isoniazid, 92%; and MDR-TB, 95%. For LPA in mycobacterial cultures, sensitivity for rifampicin was 95%; isoniazid, 96%; and MDR-TB, 90%; while specificity for rifampicin was 85%; isoniazid, 91%; and MDR-TB, 94%. Kappa coefficients were at 0.81 or above for all comparisons of LPA with CDST using sputum specimens and cultures, except for isoniazid in cultures, which was at 0.79. Conclusions This study suggests that LPA is a reliable and rapid screening test for drug-resistant TB and should be considered suitable for routine use and scale up in Peru.

Asunto(s)

RESUMEN

Objective. To determine the use and performance of a line probe assay (LPA) compared with conventional culture and drug sensitivity testing (CDST) in patients registered with tuberculosis (TB) under routine program conditions in Peru in 2011–2013. Methods. This was a descriptive, operational research, cross-sectional study of sputum specimens from patients with smear-positive pulmonary TB and mycobacterial cultures from patients with smear-negative or positive TB. Drug resistance to rifampicin and/or isoniazid detected by LPA was compared to CDST. Sensitivity, specificity, and predictive values were calculated and reliability for detecting drug resistance was assessed through kappa coefficient, with values 0.61–0.80 showing substantial correlation, and 0.81 or above showing almost-perfect correlation. Results. In 2011–2013, there were 16 169 LPA tests performed, with the proportion of TB patients receiving the test increasing from 3.2% to 30.2%. In all, 2 905 LPA test results were compared to CDST. For LPA in sputum specimens, sensitivity for rifampicin was 92%; isoniazid, 94%; and MDR-TB, 88%; while specificity for rifampicin was 92%; isoniazid, 92%; and MDR-TB, 95%. For LPA in mycobacterial cultures, sensitivity for rifampicin was 95%; isoniazid, 96%; and MDR-TB, 90%; while specificity for rifampicin was 85%; isoniazid, 91%; and MDR-TB, 94%. Kappa coefficients were at 0.81 or above for all comparisons of LPA with CDST using sputum specimens and cultures, except for isoniazid in cultures, which was at 0.79. Conclusions. This study suggests that LPA is a reliable and rapid screening test for drug-resistant TB and should be considered suitable for routine use and scale up in Peru.

Objetivo. Definir la utilización de un ensayo con sondas en línea y evaluar su desempeño, en comparación con el método convencional de cultivo y antibiograma, en los pacientes registrados con tuberculosis en condiciones programáticas en el Perú del 2011 al 2013. Métodos. Investigación operativa descriptiva con un estudio transversal de las muestras de esputo de los pacientes con diagnóstico de tuberculosis pulmonar y baciloscopia positiva y de los cultivos de micobacterias de los pacientes con tuberculosis y baciloscopia positiva o negativa. La farmacorresistencia a la rifampicina, la isoniacida o a ambas, detectada mediante el ensayo con sondas en línea, se comparó con los resultados obtenidos por el método de cultivo y antibiograma. Se calculó la sensibilidad, la especificidad y los valores predictivos del ensayo con sondas en línea y se evaluó su fiabilidad en la detección de la farmacorresistencia mediante el coeficiente k, cuyos valores de 0,61 a 0,80 correspondían a una fuerte correlación y los valores de 0,81 o superiores reflejaban una correlación casi perfecta. Resultados. Del 2011 al 2013 se practicaron 16 169 ensayos con sondas en línea, y la proporción de pacientes con diagnóstico de tuberculosis en quienes se practicaba aumentó de 3,2% a 30,2%. En total, se compararon 2 905 resultados del ensayo molecular con el método convencional. En las muestras de esputo, el ensayo molecular ofreció una sensibilidad de 92% para la resistencia a la rifampicina, 94% a la isoniacida y 88% para la tuberculosis multirresistente; su especificidad fue 92% con respecto a la rifampicina, 92% a la isoniacida y 95% a la tuberculosis multirresistente. En los cultivos de micobacterias, el ensayo con sondas en línea mostró una sensibilidad de 95% para la resistencia a la rifampicina, 96% a la isoniacida y 90% para la tuberculosis multirresistente; la especificidad fue 85% para la rifampicina, 91% para la isoniacida y 94% para la tuberculosis multirresistente. El coeficiente k fue 0,81 o superior en todas las comparaciones del ensayo molecular con el método tradicional cuando se usaron muestras de esputo y cultivo, excepto con la isoniacida en cultivo, cuyo coeficiente fue 0,79. Conclusiones. Los resultados del presente estudio indican que el ensayo con sondas en línea constituye una prueba de detección fiable y rápida para la tuberculosis multirresistente , y se debe considerar

Asunto(s)

RESUMEN

ABSTRACT Objective To determine the use and performance of a line probe assay (LPA) compared with conventional culture and drug sensitivity testing (CDST) in patients registered with tuberculosis (TB) under routine program conditions in Peru in 2011–2013. Methods This was a descriptive, operational research, cross-sectional study of sputum specimens from patients with smear-positive pulmonary TB and mycobacterial cultures from patients with smear-negative or positive TB. Drug resistance to rifampicin and/or isoniazid detected by LPA was compared to CDST. Sensitivity, specificity, and predictive values were calculated and reliability for detecting drug resistance was assessed through kappa coefficient, with values 0.61–0.80 showing substantial correlation, and 0.81 or above showing almost-perfect correlation. Results In 2011–2013, there were 16 169 LPA tests performed, with the proportion of TB patients receiving the test increasing from 3.2% to 30.2%. In all, 2 905 LPA test results were compared to CDST. For LPA in sputum specimens, sensitivity for rifampicin was 92%; isoniazid, 94%; and MDR-TB, 88%; while specificity for rifampicin was 92%; isoniazid, 92%; and MDR-TB, 95%. For LPA in mycobacterial cultures, sensitivity for rifampicin was 95%; isoniazid, 96%; and MDR-TB, 90%; while specificity for rifampicin was 85%; isoniazid, 91%; and MDR-TB, 94%. Kappa coefficients were at 0.81 or above for all comparisons of LPA with CDST using sputum specimens and cultures, except for isoniazid in cultures, which was at 0.79. Conclusions This study suggests that LPA is a reliable and rapid screening test for drug-resistant TB and should be considered suitable for routine use and scale up in Peru.

RESUMEN Objetivo Definir la utilización de un ensayo con sondas en línea y evaluar su desempeño, en comparación con el método convencional de cultivo y antibiograma, en los pacientes registrados con tuberculosis en condiciones programáticas en el Perú del 2011 al 2013. Métodos Investigación operativa descriptiva con un estudio transversal de las muestras de esputo de los pacientes con diagnóstico de tuberculosis pulmonar y baciloscopia positiva y de los cultivos de micobacterias de los pacientes con tuberculosis y baciloscopia positiva o negativa. La farmacorresistencia a la rifampicina, la isoniacida o a ambas, detectada mediante el ensayo con sondas en línea, se comparó con los resultados obtenidos por el método de cultivo y antibiograma. Se calculó la sensibilidad, la especificidad y los valores predictivos del ensayo con sondas en línea y se evaluó su fiabilidad en la detección de la farmacorresistencia mediante el coeficiente k, cuyos valores de 0,61 a 0,80 correspondían a una fuerte correlación y los valores de 0,81 o superiores reflejaban una correlación casi perfecta. Resultados Del 2011 al 2013 se practicaron 16 169 ensayos con sondas en línea, y la proporción de pacientes con diagnóstico de tuberculosis en quienes se practicaba aumentó de 3,2% a 30,2%. En total, se compararon 2 905 resultados del ensayo molecular con el método convencional. En las muestras de esputo, el ensayo molecular ofreció una sensibilidad de 92% para la resistencia a la rifampicina, 94% a la isoniacida y 88% para la tuberculosis multirresistente; su especificidad fue 92% con respecto a la rifampicina, 92% a la isoniacida y 95% a la tuberculosis multirresistente. En los cultivos de micobacterias, el ensayo con sondas en línea mostró una sensibilidad de 95% para la resistencia a la rifampicina, 96% a la isoniacida y 90% para la tuberculosis multirresistente; la especificidad fue 85% para la rifampicina, 91% para la isoniacida y 94% para la tuberculosis multirresistente. El coeficiente k fue 0,81 o superior en todas las comparaciones del ensayo molecular con el método tradicional cuando se usaron muestras de esputo y cultivo, excepto con la isoniacida en cultivo, cuyo coeficiente fue 0,79. Conclusiones Los resultados del presente estudio indican que el ensayo con sondas en línea constituye una prueba de detección fiable y rápida para la tuberculosis multirresistente, y se debe considerar apropiada su utilización en la práctica de rutina y la ampliación de su empleo en el Perú.

Asunto(s)