RESUMEN
El objetivo de este trabajo fue evaluar la resistencia a isoniacida (INH), rifampicina (RIF), estreptomicina (STR) y etambutol (EMB) de 59 cepas de Mycobacterium tuberculosis, aisladas en el período agosto 2005-diciembre 2006, en el estado Sucre, Venezuela, empleando el método de proporciones de Canetti y de nitrato reductasa. Se encontró 6,3% de resistencia primaria y 14,3% de adquirida. Una cepa fue considerada MDR, al presentar resistencia a RIF e INH. Se comparó la prueba de nitrato reductasa con el método de las proporciones, encontrándose 100% de concordancia entre los resultados de los dos métodos para INH, RIF y EMB, y 95,65% para STR. Además, la prueba nitrato reductasa produjo resultados en 10 a 14 días, comparado con 42 días para el método de proporciones, por lo que la primera se postula como una alternativa muy valiosa para acortar el tiempo de respuesta en la valoración de la susceptibilidad de M. tuberculosis. La secuencia del gen rpoB en la cepa resistente a RIF demostró la presencia de una mutación no descrita anteriormente en la región hipervariable de 81 pares de bases, donde se ha reportado el mayor número de mutaciones de cepas resistentes a RIF. Esta mutación produjo un cambio en el codón 456 de TCG > CAG. Al comparar nuestros resultados con los hallados en el último estudio de prevalencia de resistencia realizado en el estado, se demuestra una disminución en la circulación de cepas resistentes en la zona de estudio.
The objective of this study was to evaluate the resistance to isoniazid (INH), rifampicin (RIF), streptomycin (STR) and ethambutol (EMB), with the Canettis proportions method (PM) and the nitrate reductase assay (NRA) of 59 clinical strains of Mycobacterium tuberculosis, isolated in the period of august 2005 to december 2006, in Sucre state, Venezuela. Primary and acquired drug resistance was 6.3% and 14.3%, respectively. Only one strain was found to be multidrug resistant (MDR). The overall agreement between the NRA and PM was 100% for INH, RIF and EMB, and 96% for STR. The time to obtain results was 10 to 14 days for the NRA, compared to 42 days for the PM. The NRA was easy to perform and therefore represents a useful tool for rapid and accurate determination of drug-resistant M. tuberculosis. The sequence of the rpoB gene of the RIF resistant strain demonstrated a never described mutation (change in the codon 456; TCG > CAG) in the hypervariable region of 81 base pairs where most of the mutations of the RIF resistant strains have been reported. Comparison of our results with those of the last resistance prevalence study carried out in the years 1998-1999, shows a decrease in the studied area.
Asunto(s)
Humanos , Antituberculosos/farmacología , Farmacorresistencia Microbiana , Pruebas de Sensibilidad Microbiana/métodos , Mycobacterium tuberculosis/efectos de los fármacos , Tuberculosis/microbiología , Secuencia de Bases , Proteínas Bacterianas/análisis , Proteínas Bacterianas/genética , Farmacorresistencia Bacteriana Múltiple/genética , Etambutol/farmacología , Isoniazida/farmacología , Datos de Secuencia Molecular , Mutación Missense , Morbilidad/tendencias , Mycobacterium tuberculosis/enzimología , Mycobacterium tuberculosis/genética , Nitrato-Reductasa/análisis , Mutación Puntual , Prevalencia , Rifampin/farmacología , Alineación de Secuencia , Homología de Secuencia de Ácido Nucleico , Esputo/microbiología , Estreptomicina/farmacología , Tuberculosis Resistente a Múltiples Medicamentos/epidemiología , Tuberculosis Resistente a Múltiples Medicamentos/microbiología , Tuberculosis/epidemiología , Venezuela/epidemiologíaRESUMEN
OBJECTIVE: The purpose of this study was to identify chemoresistance and prognosis differences between recurrent micropapillary serous ovarian carcinoma (MPSC) and serous ovarian carcinoma. METHODS: The Extreme drug resistance (EDR) assay was performed in 13 recurrent micropapillary serous ovarian carcinoma and 56 recurrent serous ovarian carcinoma. RESULTS: Mean age of MPSC and Serous ovarian cancer were 41.1 and 58.0 respectively (p<0.05). Etoposide and Doxil were the two least resistance chemotherapeutic agents to recurrent MPSC but the most resistance agents to recurrent serous ovarian cancer. Taxol and cisplatin were the two most resistance agents to MPSC. The mean follow up was 42 months (range 1-173) The five-year overall survival rate of MPSC and serous ovarian carcinoma were 71.6% and 33.9% respectively. The mean survival were 136 months in MPSC compared with 72 months in serous ovarian carcinoma (p<0.035). CONCLUSION: In this retrospective analysis, MPSC showed very different in EDR results and favorable prognosis compare to serous ovarian carcinoma.
Asunto(s)
Cisplatino , Resistencia a Medicamentos , Etopósido , Estudios de Seguimiento , Neoplasias Ováricas , Paclitaxel , Pronóstico , Estudios Retrospectivos , Tasa de SupervivenciaRESUMEN
To identify herpesviral virions secreted by viral replication, we have established the nuclease-resistance assay (NRA) as a comparative analysis to other conventional assays, including electron microscopy (EM). For this study, we used an efficient experimental in vitro infection model for Alcelaphine herpesvirus 1 (AlHV-1), a gamma herpesvirus, to propagate the virus. The NRA could identify extracellular, cell-free, enveloped virions in the supernatants after 24 hours post inoculation (h.p.i.) of AlHV-1. The results of EM observation were correlated with those of NRA. Mature virions were observed in the clarified, concentrated supernatants from 24 h.p.i. by EM. These results show that sensitivity of the NRA is comparable with that of EM for the identification of mature enveloped virions, which directly presents evidence of herpesviral lytic replication. NRA allows us to differentiate the virus from other member of Herpesviridae, and has extended the possibility of analysis for quantification of shedding viruses when used in conjunction with real-time polymerase chain reaction (PCR).