RFLP patterns and risk factors for recent tuberculosis transmission among hospitalized tuberculosis patients in Rio de Janeiro, Brazil.

Isolates of Mycobacterium tuberculosis from 120 tuberculosis patients seen in the 12 months ending September 1994 at 2 tertiary-care centres in Rio de Janeiro were characterized by IS6110 restriction fragment length polymorphism (RFLP) analysis. Ninety-seven patients (81%) had isolates with unique RFLP patterns, while 23 patients (19%) had isolates that belonged to 11 different RFLP cluster patterns. The strains from the latter patients were distributed among 1 group of 3 patients and 10 groups of 2 patients each. The cluster-pattern strains were not associated with gender, age, HIV infection, type of residence, living in shelter, homelessness or previous history of tuberculosis. However, clustering was strongly associated with multidrug resistance (P = 0.006). These data suggest that recent exogenous transmission may be important for the development of new cases of multidrug-resistant disease in patients attending tertiary-care centres in Rio de Janeiro, Brazil.

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

DNA fingerprinting of Mycobacterium tuberculosis from patients with and without AIDS in Rio de Janeiro.

Isolates of Mycobacterium tuberculosis derived from patients with AIDS from a single hospital in Rio de Janeiro were typed using a standardized RFLP technique detecting IS6110 polymorphism. Nineteen isolates were obtained from 15 different patients. Eleven distinct IS6110 patterns were found, with 4 banding patterns shared by 2 patients. The clustering value of 53% was much higher in comparison with clustering of M. tuberculosis strains from TB patients without clinical signs for HIV infection from randomly selected health centers. We present these results as preliminary data on M. tuberculosis strain polymorphism in Brazil and on the higher risk for recent transmission amongst patients with AIDS.

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.

DNA fingerprinting of mycobacterium tuberculis from patients with and without AIDS in Rio de Janeiro

Isolates of Mycobacterium tuberculosis derived from patients with AIDS from a single hospital in Rio de Janeiro were typed using a standardized RFLP technique detecting IS6110 polymorphism. Nineteen isolates were obtained from 15 different patients. Eleven distinct IS6110 patterns were found, with 4 banding patterns shared by 2 patients. The clustering value of 53 percent was much higher in comparison with clustering of M. tuberculosis strains from TB patients without clinical signs for HIV infection from randomly selected health centers. We present these results as preliminary data on M. tuberculosis strain polymorphism in Brazil and on the higher risk for recent transmission amongst patients with AIDS.

Mycobacteremia in patients with the acquired immunodeficiency syndrome.

BACKGROUND: Bacillemia is a key event in the pathogenesis of tuberculosis. Although current evidence indicates that Mycobacterium tuberculosis bacteremia is rare in patients seronegative for the human immunodeficiency virus, it has been increasingly reported in patients with the acquired immunodeficiency syndrome (AIDS). OBJECTIVE: To determine clinical and laboratory characteristics of patients with AIDS and tuberculosis with and without bacillemia. METHODS: Fifty patients with AIDS with clinical suspicion of disseminated mycobacterial disease were prospectively selected. Three consecutive blood samples were collected for culture using a standardized protocol. RESULTS: Mycobacterium was isolated from any body site in 42 patients (84%). Bacillemia was detected in 30 (71.4%) of these 42 patients: 11 (28.2%) caused by Mycobacterium avium-intracellulare complex and 19 (71.8%) caused by M tuberculosis. Blood culture was the only method used to confirm the diagnosis in 5 (15%) of the 33 tuberculosis cases. Tuberculosis in patients with AIDS developed with nonspecific insidious symptoms, a remarkable elevated alkaline phosphatase level, and without the classic miliary radiological pattern. We could demonstrate 2 previously unrevealed clinical characteristics of bacteremic tuberculosis in patients with AIDS: a shift to the left in the white blood cell count and abdominal lymph node enlargement. In patients with tuberculosis, the in-hospital mortality rate was higher among patients with bacillemia, although the posttreatment survival rate was comparable. CONCLUSIONS: Blood culture is a valuable tool to confirm the clinical diagnosis of disseminated tuberculosis in patients with AIDS and can distinguish patients with characteristic clinical findings and outcome. Abdominal ultrasonography may be an additional helpful tool to identify these patients.

Diagnosis of disseminated mycobacterial infection: testing a simple and inexpensive method for use in developing countries.

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 of a biphasic medium, and (2) a non-commercial lysis-centrifugation method. A total of 3 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 non-commercial lysis-centrifugation technique is inexpensive, reliable, and can be an alternative method for the diagnosis of mycobacteraemia in developing countries.

Mycobacterial flora of the skin in leprosy.

The presence of mycobacteria on the skin of healthy people and in leprosy lesions has been documented previously. The present study observed the mycobacterial flora on the hands (by the hand-washing method) and fingers (by the inoculated culture medium using scraped material obtained during the preparation of slit-skin smears) in 89 untreated leprosy patients. We also evaluated the slit-skin smears from fingers for the diagnosis of leprosy. In 16 patients (17.9%) mycobacteria were cultured from scrapings and hand washings. The frequency of isolates from lepromatous (LL) leprosy cases (52.9%) was significantly higher than from tuberculoid (TT) leprosy cases (5.2%). It was observed that Mycobacterium avium and M. scrofulaceum were the only opportunistic mycobacteria isolated from multibacillary patients, and two hypotheses are discussed to explain these findings. The slit-skin smears from fingers were as satisfactory as smears from other sites for the diagnosis of leprosy, but they were less satisfactory for estimating the morphological index.