RESUMEN
OBJECTIVE: A multicentre evaluation was performed to assess two rapid low-cost methods, MTT (3-[4.5-dimethylthiazol-2-yl]-2.5-diphenyltetrazolium bromide) and resazurin assays, for testing the susceptibility of Mycobacterium tuberculosis to the first-line anti-tuberculosis drugs rifampicin (RMP), isoniazid (INH), ethambutol (EMB) and streptomycin (SM). METHODS: Thirty coded M. tuberculosis strains were sent to seven laboratories located in Latin America, representing six countries. Each site performed the colorimetric assays, MTT and resazurin, blind for the first-line drugs RMP, INH, EMB and SM. The minimum inhibitory concentration results obtained were compared to the conventional proportion method on Lowenstein-Jensen medium. RESULTS: After establishing the breakpoint concentrations, excellent results were obtained for RMP, INH and EMB, with levels of specificity and sensitivity of between 96% and 99%. CONCLUSION: MTT and resazurin assays are promising, accessible new alternative methods for middle- and low-resource countries that need low-cost methods to perform rapid susceptibility testing of M. tuberculosis to key anti-tuberculosis drugs.
Asunto(s)
Antituberculosos/farmacología , Mycobacterium tuberculosis/efectos de los fármacos , Colorantes , Farmacorresistencia Bacteriana , Humanos , Indicadores y Reactivos , América Latina , Pruebas de Sensibilidad Microbiana , Mycobacterium tuberculosis/patogenicidad , Oxazinas , Valores de Referencia , Reproducibilidad de los Resultados , Sales de Tetrazolio , Tiazoles , Tuberculosis Pulmonar/tratamiento farmacológico , XantenosRESUMEN
A case of an HIV negative female patient with coxofemoral arthritis of tuberculous etiology, multidrug-resistant strain, and connective tissue disease associated to glucocorticoid therapy is reported. The patient was treated with cycloserine, ethambutol, p-aminosalicylic acid and ofloxacin, with improvement of the joint lesions. Previous publications on this subject are reviewed.
Asunto(s)
Artritis Infecciosa/microbiología , Articulación de la Cadera/microbiología , Mycobacterium tuberculosis , Tuberculosis Resistente a Múltiples Medicamentos/complicaciones , Tuberculosis Osteoarticular/complicaciones , Adulto , Artritis Infecciosa/tratamiento farmacológico , Femenino , Fémur/microbiología , Humanos , Tuberculosis Resistente a Múltiples Medicamentos/tratamiento farmacológico , Tuberculosis Resistente a Múltiples Medicamentos/microbiología , Tuberculosis Osteoarticular/tratamiento farmacológico , Tuberculosis Osteoarticular/microbiologíaRESUMEN
A previously proposed MGIT protocol was assessed focussing on its reliability to test the mainstay antituberculous drugs. Isoniazid (H) (0.1 mg/l) and rifampin (R) (1 mg/l) were assayed against 109 Mycobacterium tuberculosis isolates affecting patients at high risk of multidrug-resistant tuberculosis. All isolates were simultaneously tested on Löwenstein-Jensen medium by the proportion method considered the gold standard. MGIT readings were accomplished within 2 and 22 days after inoculation, at day 10, 93.4% of the tests were completed. Unsatisfactory to evaluate H activity, the assay misclassified 8.8% (5/57) H susceptible and 7.7% (4/52) H resistant isolates. Otherwise, it yielded correct results for all 60 R susceptible isolates and 93.9% (46/49) R resistant isolates. Properly backed-up by a conventional test and targeting high risk patients, the MGIT system proved to be a useful aid to anticipate most of resistance to R. Accuracy, cost and turnaround time were competitive compared with those of semi-automated culture-based or molecular methods.
Asunto(s)
Antituberculosos/farmacología , Farmacorresistencia Bacteriana Múltiple , Resistencia a Medicamentos , Isoniazida/farmacología , Mycobacterium tuberculosis/efectos de los fármacos , Juego de Reactivos para Diagnóstico , Rifampin/farmacología , Medios de Cultivo , Reacciones Falso Negativas , Infecciones por VIH/complicaciones , Humanos , Mycobacterium tuberculosis/crecimiento & desarrollo , Mycobacterium tuberculosis/aislamiento & purificación , Recurrencia , Estándares de Referencia , Factores de Riesgo , Sensibilidad y Especificidad , Tuberculosis/complicaciones , Tuberculosis/microbiologíaRESUMEN
Patients with mutations in the IFNgamma/IL-12 pathway show an exquisite susceptibility to mycobacterial diseases. An IL-12Rbeta1 deficient patient with impaired intestinal absorption suffered from a 13 year culture-positive Mycobacterium bovis-BCG infection with acquired multidrug resistance. A combined parenteral and enteral anti-mycobacterial treatment, including recombinant IFNgamma, helped to clear his infection.
Asunto(s)
Antituberculosos/uso terapéutico , Mycobacterium bovis/aislamiento & purificación , Receptores de Interleucina-12/deficiencia , Tuberculosis/tratamiento farmacológico , Tuberculosis/genética , Adolescente , Antituberculosos/efectos adversos , Predisposición Genética a la Enfermedad , Humanos , Masculino , Receptores de Interleucina-12/genética , Tuberculosis/microbiologíaRESUMEN
A previously proposed MGIT protocol was assessed focussing on its reliability to test the mainstay antituberculous drugs. Isoniazid (H) (0.1 mg/l) and rifampin (R) (1 mg/l) were assayed against 109 Mycobacterium tuberculosis isolates affecting patients at high risk of multidrug-resistant tuberculosis. All isolates were simultaneously tested on L÷wenstein-Jensen medium by the proportion method considered the gold standard. MGIT readings were accomplished within 2 and 22 days after inoculation, at day 10, 93.4
of the tests were completed. Unsatisfactory to evaluate H activity, the assay misclassified 8.8
(5/57) H susceptible and 7.7
(4/52) H resistant isolates. Otherwise, it yielded correct results for all 60 R susceptible isolates and 93.9
(46/49) R resistant isolates. Properly backed-up by a conventional test and targeting high risk patients, the MGIT system proved to be a useful aid to anticipate most of resistance to R. Accuracy, cost and turnaround time were competitive compared with those of semi-automated culture-based or molecular methods.