RESUMEN
In this study we evaluated the crystal violet decolorization assay (CVDA) for detection of minimum inhibitory concentration (MIC) of antituberculosis drugs. 53 isolates were tested in this study and 13 of them were multidrug resistant (MDR) isolates. The antibiotics concentrations were 2-0.06 mg/L for isoniazid (INH) and rifampicin (RIF) and were 16-0.25 mg/L for streptomycin (STM) and ethambutol (EMB). Crystal violet (CV-25 mg/L) was added into the microwells on the seventh day of incubation and incubation was continued until decolorization. Decolorization of CV was the predictor of bacterial growth. Overall agreements for four drugs were detected as 98.1%, and the average time was detected as 9.5 ± 0.89 day after inoculation. One isolate for INH and two isolates for STM were determined resistant in the reference method, but susceptible by the CVDA. One isolate was susceptible to EMB by the reference method, but resistant by the CVDA. All results were concordant for RIF. This study shows that CVDA is a rapid, reliable and suitable for determination of MIC values of Mycobacterium tuberculosis. And it can be used easily especially in countries with limited-sources.
Asunto(s)
Humanos , Antituberculosos/farmacología , Mycobacterium tuberculosis/efectos de los fármacos , Antituberculosos/administración & dosificación , Bioensayo , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Etambutol/administración & dosificación , Etambutol/farmacología , Violeta de Genciana/química , Indicadores y Reactivos/química , Isoniazida/administración & dosificación , Isoniazida/farmacología , Pruebas de Sensibilidad Microbiana/métodos , Mycobacterium tuberculosis/crecimiento & desarrollo , Rifampin/administración & dosificación , Rifampin/farmacología , Estreptomicina/administración & dosificación , Estreptomicina/farmacología , Tuberculosis Resistente a Múltiples Medicamentos/microbiologíaRESUMEN
The purpose of this study is to evaluate four rapid colourimetric methods, including the resazurin microtitre assay (REMA), malachite green decolourisation assay (MGDA), microplate nitrate reductase assay (MNRA) and crystal violet decolourisation assay (CVDA), for the rapid detection of multidrug-resistant (MDR) tuberculosis. Fifty
Asunto(s)
Humanos , Antituberculosos/farmacología , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Pruebas de Sensibilidad Microbiana/métodos , Mycobacterium tuberculosis/efectos de los fármacos , Colorantes , Indicadores y Reactivos , Sensibilidad y EspecificidadRESUMEN
The microplate nitrate reductase assay (MNRA) and the rezasurin microtitre assay (REMA) were used for the susceptibility testing of 73 clinical isolates and the results were compared with those that were obtained using the Bactec 460 TB and Bactec MGIT 960 systems. The REMA and the MNRA were performed in 96-well plates. For the REMA, the concentrations of isoniazid (INH) and rifampicin (RIF) ranged from 1.0-0.01 µg/mL and 2.0-0.03 µg/mL, respectively. For the MNRA, the INH concentration was between 1.0-0.03 µg/mL and the RIF concentration was between 2.0-0.06 µg/mL. For the MNRA, the sensitivity, specificity, positive predictive value, negative predictive value and INH/RIF agreement were 100/95.6, 97.6/100, 96.8/100, 100/98 and 98.6/98.6, respectively, and for the REMA, they were 100/91.3, 90.4/100, 88.5/100, 100/96.1 and 94.5/97.2, respectively. Our data suggest that these two rapid, low-cost methods may be inexpensive, alternative assays for the rapid detection of multidrug resistant tuberculosis in low-income countries.
Asunto(s)
Humanos , Antituberculosos/farmacología , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Isoniazida/farmacología , Pruebas de Sensibilidad Microbiana/métodos , Mycobacterium tuberculosis/efectos de los fármacos , Rifampin/farmacología , Mycobacterium tuberculosis/aislamiento & purificación , Nitrato-Reductasa/metabolismo , Oxazinas/metabolismo , Valor Predictivo de las Pruebas , Juego de Reactivos para Diagnóstico , Sensibilidad y Especificidad , Tuberculosis Resistente a Múltiples Medicamentos/microbiología , Xantenos/metabolismoRESUMEN
The susceptibility of 49 Mycobacterium tuberculosis clinical isolates to isoniazid (INH) and rifampisin (RIF) (28 multi-drug resistant-tuberculosis samples) was determined by a nitrate reductase assay (NRA) on blood agar. Agreement between the NRA and other testing methods was found to be 93.8 percent for both INH and RIF. The sensitivity, specificity, positive predictive value and negative predictive value for INH were 92.8 percent, 94.2 percent, 86.6 percent and 97 percent, respectively. The sensitivity, specificity, positive predictive value and negative predictive value for RIF were 90.4 percent, 96.4 percent, 95 percent and 93.1 percent. In conclusion, we show here that blood agar can be used effectively for the NRA test.
Asunto(s)
Humanos , Antituberculosos , Farmacorresistencia Bacteriana Múltiple , Isoniazida , Mycobacterium tuberculosis , Rifampin , Agar , Pruebas de Sensibilidad Microbiana , Nitrato-Reductasa , Valor Predictivo de las Pruebas , Sensibilidad y Especificidad , Tuberculosis Resistente a Múltiples MedicamentosRESUMEN
In this study, we have evaluated the broth microdilution method (BMM) for susceptibility testing of Mycobacterium tuberculosis. A total of 43 clinical isolates of M. tuberculosis and H37Rv as a control strain were studied. All isolates were tested by the proportion method and the BMM for isoniazid (INH), rifampicin (RIF), streptomycin (STR), and ethambutol (ETM). The proportion method was carried out according to the National Committee for Clinical Laboratory Standards (NCCLS) on Lõwenstein-Jensen (LJ) medium. The BMM was carried out using 7H9 broth with 96 well-plates. All strains were tested at 3.2-0.05 µg/ml, 16-0.25 µg/ml, 32-0.5 µg/ml, and 32-0.5 µg/ml concentrations for INH, RIF, STR, and ETM, respectively. When the BMM was compared with the proportion method, sensitivity was 100, 100, 96.9, and 90.2 percent, while specificity was 100, 85.7, 90.9, and 100 percent for INH, RIF, STR, and ETM, respectively. The plates were examined 7, 10, 14, and 21 days after incubation. The majority of the result were obtained at 14th days after incubation, while the proportion method result were ended in 21-28 days. According to our results, it may be suggested that the BMM is suitable for early determining of multidrug-resistance-M. tuberculosis strains in developed or developing countries.
Asunto(s)
Humanos , Antituberculosos , Mycobacterium tuberculosis , Farmacorresistencia Microbiana , Etambutol , Isoniazida , Pruebas de Sensibilidad Microbiana , Rifampin , Sensibilidad y Especificidad , EstreptomicinaRESUMEN
OBJECTIVES: Outcome after acute hepatitis B virus (HBV) infection may be determined by the host immune system. We studied the distribution of major histocompatibility (MHC) antigens in patients who developed natural immunity against HBV and those with chronic hepatitis B. METHODS: Thirty patients positive for IgG anti-HBs and anti-HBc ('naturally immune'), 30 patients with HBsAg-positive chronic hepatitis and 30 subjects with no serological markers of HBV infection (controls) were studied. MHC class-I antigens were detected by the standard Terasaki microlymphocytotoxicity test and the MHC class-II antigens by a polymerase chain reaction using sequence-specific primers. RESULTS: In the naturally immune group, A11, B73, CW3, DRB1*16 and DQB1*05 antigens were significantly more frequent than in the control group, and B73, DRB1*04 and DRB1*13 antigens were more frequent than in the chronic hepatitis group. In the chronic hepatitis group, CW6, DRB5 and DQB1*05 antigens were significantly more frequent than in the control group, and B8, CW7, DRB1*03 and DQB1*02 antigens were more frequent than in the naturally immune group. CONCLUSIONS: Differences in alleleic frequencies of HLA among persons with natural immunity against HBV and those with chronic hepatitis B may suggest a genetic basis for persistence of HBV infection and occurrence of chronic liver disease.
Asunto(s)
Adulto , Estudios de Casos y Controles , Femenino , Antígenos HLA/inmunología , Hepatitis B Crónica/inmunología , Humanos , Complejo Mayor de Histocompatibilidad/inmunología , Masculino , Pronóstico , Factores de RiesgoRESUMEN
The aim of this study was to investigate the correlation between proportion method with mycobacteria growth indicator tube (MGIT) and E-test for Mycobacterium tuberculosis. Forty clinical isolates were tested. MGIT and E-test with the first line antituberculous drugs correlated with the proportion method. Our results suggested that MGIT and E-test methods can be routinely used instead of the proportion method