Diagnóstico bacteriológico de la tuberculosis en Argentina: resultados de una encuesta nacional Bacteriological diagnosis of tuberculosis in Argentina: results of a national survey

Con el objetivo de evaluar recursos, prácticas y medidas de bioseguridad utilizados en el diagnóstico bacteriológico de tuberculosis y determinar la utilidad y alcance de las técnicas empleadas, se llevó adelante una encuesta transversal a laboratorios del sector público de Argentina utilizando un cuestionario estructurado. El análisis de los resultados mostró que la densidad de centros de microscopía y cultivo se encuentra al nivel o encima de lo recomendado por Organización Mundial de la Salud. El programa de control de calidad de microscopía cubre mayoritariamente los laboratorios con alta carga de trabajo. El promedio de baciloscopías/paciente fue bajo (1,6). El 25% de los laboratorios de cultivo empleaban protección respiratoria inadecuada. El aporte del cultivo a la confirmación de casos pulmonares en las jurisdicciones estuvo asociado a la proporción de muestras cultivadas. Globalmente, el porcentaje de pacientes pulmonares baciloscopía-negativa que fue confirmado bacteriológicamente fue de 18.9%; mientras que la may-oría de los casos extrapulmonares se confirmó sólo por cultivo (71,3%). Es prioritario aún el incremento del número de esputos estudiados por baciloscopía y cultivo, así como aumentar la cobertura de programa de control de calidad de microscopía; es fundamental proveer al personal de laboratorio de adecuada protección respiratoria y evaluación médica regular.<br>In order to assess laboratory resources, practices, and biosafety measures during mycobacterial testing and determine the usefulness and scope of mycobacterial techniques, a cross-sectional survey of public laboratories was conducted in Argentina using a structured questionnaire. Sputum smear analysis showed that both smear and culture testing centers are being provided at or above the WHO recommended density for such facilities. The microscopy quality assessment program covered most high-demand laboratories. Mean number of sputum smears per patient was low (1.6). The use of inadequate personal respiratory protection was identified in 25% of culture laboratories. Jurisdictions that cultured a higher proportion of their smear-tested sputa identified a higher proportion of smear-negative cases. The percentage of smear negatives among all bacteriologically confirmed pulmonary cases was 18.9%, while most extrapulmonary cases were confirmed by culture (71.3%). In conclusion, increasing the number of sputa studied by microscopy and culture (while expanding the coverage of the quality assessment program) is a priority; adequate respiratory protection and regular medical evaluation of laboratory staff is still needed in some laboratories

Rapid detection of tuberculous and non-tuberculous mycobacteria by polymerase chain reaction amplification of a 162 bp DNA fragment from antigen 85.

A polymerase chain reaction (PCR) assay was developed for detection of mycobacteria using amplification of a 162 bp region of the genes coding for the mycobacterial antigen 85 complex. Strains belonging to the Mycobacterium tuberculosis complex were further differentiated from non-tuberculous mycobacteria by hybridization of the PCR derived Southern blot with an internal oligonucleotide probe and washing under stringent conditions. The method allowed rapid and sensitive detection of mycobacterial DNA in uncultured clinical samples. PCR results obtained for Mycobacterium tuberculosis in 206 specimens from 180 untreated patients gave a sensitivity of 93.9% and a specificity of 94.3% compared with the culture. PCR detected DNA from Mycobacterium tuberculosis in seven samples from patients with clinically evident tuberculosis in whom culture was negative. The results suggest that this PCR assay could be used for early and specific diagnosis of tuberculosis.Journal ArticleResearch Support, Non-U.S. Gov'tSCOPUS: ar.jinfo:eu-repo/semantics/publishe