Drug Resistance Patterns among Hospitalized Tuberculous Patients in Rio de Janeiro, Brazil, 1993-1994

The purpose of this study was to analyze the prevalence and risk factors for drug resistance among hospitalized patients in two tertiary care centers, an acquired immunodeficiency syndrome (AIDS) reference center and a sanatorium, in Rio de Janeiro, Brazil. From 1993-1994, 389 patients were diagnosed as having tuberculosis (TB). Isolates from 265 patients were tested for in vitro susceptibility to rifampin and isoniazid. Resistance to one or more drugs was detected in 44 patients (16.6 percent) and was significantly more common among recurrent cases in both hospitals (p=0.03 in the AIDS center and p=0.001 in the sanatorium). Twenty seven patients (10.2 percent) had isolates resistant to both isoniazid and rifampin. Multi-drug resistance was associated with human immunodeficiency virus (HIV) infection among patients who had never been treated for TB. In conclusion, drug-resistant TB is high in hospitalized patients in Rio de Janeiro, especially among HIV infected patients. Therefore, measures to control TB and prevent nosocomial transmission need urgently to be set up in the Brazilian hospitals

Diagnóstico de la infección micobacteriana diseminada: evaluación de un método sencillo y barato para países en desarrollo / Diagnosis of disseminated mycobacterial infection: testing a simple and inexpensive method for use in developing countries

Con el desarrollo de la epidemia del síndrome de inmunodeficiencia adquirida (sida), el aislamiento de micobacterias de la sangre se ha convertido en un problema habitual de los laboratorios clínicos. En el presente estudio se evaluaron dos métodos para aislar micobacterias en muestras de sangre de pacientes de sida: 1) la inoculación directa en un medio bifásico y 2) un método no comercializado de lisis por centrifugación. A cada uno de los 50 pacientes de sida con sospecha de enfermedad micobacteriana diseminada se le extrajeron tres muestras de sangre consecutivas a intervalos de 15 minutos. En 70 de 138 muestras de sangre obtenidas de 30 (60%) pacientes se detectó crecimiento de micobacterias. A partir de estos cultivos, en 19 pacientes se aisló Mycobacterium tuberculosis y en 11 (37%), el complejo Mycobacterium avium. Los cultivos en que se utilizó el método de lisis por centrifugación fueron positivos en 54% de los pacientes, mientras que esta cifra se redujo a 44% en los cultivos en que se usó el método bifásico (P > 0,05). El porcentaje de muestras positivas al complejo M. avium fue mayor con el método de centrifugación por lisis (91%) que con el de inoculación directa en medio bifásico (45,4%) (P < 0,05). Sin embargo, los porcentajes de muestras positivas a M. tuberculosis detectadas con el método de lisis por centrifugación (89,5%) y con el de inoculación directa en un medio bifásico (100%) fueron similares (P > 0,05). La técnica no comercializada de centrifugación por lisis es barata, fiable y puede constituir un método alternativo para el diagnóstico de micobacteriemia en países en desarrollo.

With the development of the acquired immunodeficiency syndrome (AIDS) epidemic, the isolation of mycobacteria from blood has become a common problem for clinical laboratories. In this study two methods were used for the recovery of mycobacteria from blood specimens obtained from AIDS patients: (1) direct inoculation in biphasic medium, and (2) a noncommercial lysis-centrifugaton method. A total of three consecutive blood samples were taken at 15-minute intervals from each of 50 AIDS patients with clinical suspicion of disseminated mycobacterial disease. Mycobacterium growth was noted in 70/138 blood specimens from 30 (60%) patients. These cultures yielded Mycobacterium tuberculosis in 19 (63%) and Mycobacterium avium complex organisms in 11 (37%) patients. Cultures using the lysis-centrifugation method were positive in 54% of the patients, while cultures using biphasic medium were positive in 44% (P > 0,05). The positivity for M. avium complex was higher with lysis-centrifugation (91%) than with biphasic medium (45,4%) (P < 0,05). However, the positivities for M. tuberculosis with the lysis-centrifugation method (89,5%) and direct inoculation in biphasic medium (100%) were similar (P > 0,05). The use of a noncommercial lysis-centrifugation technique is inexpensive, reliable, and can be an alternative method for the diagnosis of mycobacteremia in developing countries.