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Introducción. El diagnóstico temprano de tuberculosis permite el control de la enfermedad y su transmisibilidad. Objetivo. Describir la validez diagnóstica del GeneXpert MTB/RIF para Mycobacterium tuberculosis en muestra bronquial, utilizando como referencia el cultivo Löwenstein Jensen. Metodología. Estudio transversal analítico, mediante revisión de 942 registros de la Unidad de Broncoscopía durante el año 2014 al 2018, de las cuales 320 cumplieron criterios de inclusión. Estos datos fueron exportados a un formato compatible con Epi Info versión 7 y analizados con parámetros estadísticos de sensibilidad, especificidad, valor predictivo positivo, valor predictivo negativo, prueba de concordancia e índice Kappa Epidat 4,2. Resultados. De los 320 pacientes sometidos a fibrobroncoscopía diagnóstica para tuberculosis con GeneXpert MTB/RIF, los resultados negativos fueron 79 % (252) y positivo 21 % (68); el 1 % mostró resistencia a rifampicina. Se reportó una fuerte concordancia de GeneXpert MTB/RIF con el cultivo bacilo ácido alcohol resistente, que se determinó con un índice de kappa de 0,88 +/- (0,81-0,94) IC 95 %, una sensibilidad del 98 %, especificidad del 96 %, valor predictivo positivo 83 % (IC 95 %), valor predictivo negativo 99,6 % (CI 95 %). Conclusión. La prueba GeneXpert MTB/RIF tiene una capacidad altamente sensible y específica para el diagnóstico de tuberculosis en muestras obtenidas por fibrobroncoscopía
Introduction. The early diagnosis of tuberculosis allows the control of the disease and its transmissibility. Objective. Describe the diagnostic validity of GeneXpert MTB / RIF for Mycobacterium tuberculosis in bronchial sample using the Löwenstein Jensen culture as reference. Methodology. Analytical cross-sectional study, through a review of 942 records of the Bronchoscopy Unit during the year 2014 to 2018, of which 320 met inclusion criteria. These data were exported to a format compatible with Epi Info version 7, analyzed with statistical parameters of sensitivity, specificity, positive predictive value, negative predictive value, concordance test, and Kappa Epidat index 4,2. Results. Of the 320 patients who underwent diagnostic bronchoscopy for tuberculosis with GeneXpert MTB / RIF, the negative results were 79 % (252), and positive 21 % (68), 1 % showed genetic resistance to rifampicin. A strong concordance of GeneXpert MTB / RIF was reported with the acid-alcohol-resistant bacillus culture determined with a kappa index of 0,88 +/- (0,81-0,94) 95 % CI, a sensitivity of 98 %, specificity 96 %, positive predictive value 83 % (95 % CI), negative predictive value 99,6 % (95 % CI). Conclusions. The GeneXpert MTB / RIF Test has a highly sensitive and specific capacity for the diagnosis of tuberculosis in samples obtained by bronchoscopy
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Rifampin , Tuberculosis , Mycobacterium tuberculosis , BroncoscopíaRESUMEN
Shiga toxin-producing Escherichia coli (STEC) and Listeria monocytogenes are worldwide recognized zoonotic pathogens. Recent reports have emerged about the circulation of antimicrobial-resistant STEC and L. monocytogenes isolates. To assess the frequency of antimicrobial resistance and related genes in these pathogens, we studied 45 STEC and 50 L. monocytogenes isolates locally recovered from different sources. Antimicrobial susceptibility testing was performed by disk-diffusion method, and the genomic sequences of three selected STEC and from all 50 L. monocytogenes isolates were analyzed for antibiotic resistance genes. Four STEC and three L. monocytogenes isolates were phenotypically resistant to at least one of the antibiotics tested. Resistance genes aph(3â³)-Ib, aph(3')-Ia, aph(6)-Id, bla T EM-1B, sul2, mef (A), and tet(A) were found in a human STEC ampicillin-resistant isolate. All L. monocytogenes isolates harbored fosX, lin, mdrL, lde fepA, and norB. Overall resistance in L. monocytogenes and STEC was low or middle. However, the high load of resistance genes found, even in susceptible isolates, suggests that these pathogens could contribute to the burden of antimicrobial resistance.
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Comamonas kerstersii is a non-fermenting Gram-negative bacillus. It has been associated with intra-abdominal infections. We describe a clinical case of bacteremia caused by C. kerstersii in a young man with acute appendicitis. The first identification, using the Vitek2 compact system (BioMerieux) from blood cultures, was Comamonas testosteroni. However, using MALDI-TOF was identified as C. kerstersii. The patient was treated first with ampicillin sulbactam and then piperacillin tazobactam with favorable evolution. Within the genus Comamonas, C. testosteroni has been the most frequently reported species as a cause of infections in humans, only 23 cases of C. kerstersii being described. Given the problems of phenotypic identification of these microorganisms, it is possible that some C. testosteroni reports could have corresponded to C. kerstersii. This case highlights the pathogenic role of C. kerstersii and the importance of using MALDI-TOF as a diagnostic tool for non-fermenting Gram-negative bacilli identification.