Rentabilidad de la baciloscopia y el cultivo en muestras de jugo gástrico para el diagnóstico de la tuberculosis

Abstract

ObjectiveTo evaluate the effectiveness of smears and cultures in gastric juice samples in the diagnosis of childhood pulmonary tuberculosis and to assess the relationship between clinical, radiological and epidemiological parameters in children with tuberculosis. MethodsBlind, prospective, controlled study of 421 gastric aspirate samples from 139 children referred because of suspected tuberculosis. Children were classified according to clinico-radiological factors, irrespective of microbiological results. To verify the clinical diagnosis an extended follow- up was carried out. ResultsSmears were positive in 6 of the 46 children with active tuberculosis (sensitivity: 13%) and in 3 of the 93 children in the control groups (specificity: 96.8%). Cultures were positive in 15 children with active disease (sensitivity: 32.6%) and effectiveness was greater when the chest radiograph showed parenchymal involvement. Mycobacterium tuberculosis was also isolated in two children with tuberculous infection who showed no apparent signs of the disease and in one of these children, CT-scan revealed mediastinal adenopathies which were not evident on the chest radiograph. Mean growth time for positive cultures was 42 days. ConclusionThe sensitivity of smears and cultures in gastric aspirate samples of children with pulmonary tuberculosis is low. Results of culture take several weeks and smears can give false positive results. Some children with tuberculous infection without apparent signs of the disease show microbiological activity that can be caused by mediastinal adenopathies that are not evident on chest radiographs.