Synthesis, characterization, and in vitro evaluation of gamma radiationinduced PEGylated isoniazid

Background: The search for innovative anti-tubercular agents has received increasing attention in tuberculosis chemotherapy because Mycobacterium tuberculosis infection has steadily increased over the years. This underlines the necessity for new methods of preparation for polymer-drug adducts to treat this important infectious disease. The use of poly(ethylene glycol)(PEG) is an alternative producing anti-tubercular derivatives. However, it is not yet known whether PEGylated isonicotinylhydrazide conjugates obtained by direct links with PEG are useful for therapeutic applications. Results: Here, we synthesized a PEGylated isoniazid (PEG-g-INH or PEG­INH) by gamma radiation-induced polymerization, for the first time. The new prodrugs were characterized using Raman and UV/Vis spectrometry. The mechanism of PEGylated INH synthesis was proposed. The in vitro evaluation of a PEGylated isonicotinylhydrazide macromolecular prodrug was also carried out. The results indicated that PEG­INH inhibited the bacterial growth above 95% as compared with INH, which showed a lower value (80%) at a concentration of 0.25 µM. Similar trends are observed for 0.1, 1, and 5 µM. Conclusions: In summary, the research suggests that it is possible to covalently attach the PEG onto INH by the proposed method and to obtain a slow-acting isoniazid derivative with little toxicity in vitro and higher antimycobacterial potency than the neat drug.

Natural Compounds from Mexican Medicinal Plants as Potential Drug Leads for Anti-Tuberculosis Drugs

ABSTRACT In Mexican Traditional Medicine 187 plant species are used in the treatment of respiratory conditions that may be associated with tuberculosis. In this contribution, we review the ethnobotany, chemistry and pharmacology of 63 species whose extracts have been assayed for antimycobacterial activity in vitro. Among these, the most potent is Aristolochia brevipes (MIC= 12.5 µg/mL), followed by Aristolochia taliscana, Citrus sinensis, Chrysactinia mexicana, Persea americana, and Olea europaea (MIC<64 µg/mL). Other potent extracts (inhibition > 95%, 50 µg/mL) include: Amphipterygium adstringens, Larrea divaricata, and Phoradendron robinsoni. Several active compounds have been identified, the most potent are: Licarin A (isolated from A. taliscana), and 9-amino-9-methoxy-3,4-dihydro-2H-benzo[h]-chromen-2-one (transformation product of 9-methoxytariacuripyrone isolated from Aristolochia brevipes), both with MIC= 3.125 µg/mL, that is 8-fold less potent than the reference drug Rifampicin (MIC= 0.5 µg/mL). Any of the compounds or extracts here reviewed has been studied in clinical trials or with animal models; however, these should be accomplished since several are active against strains resistant to common drugs.

Descripción de las mutaciones de Mycobacterium tuberculosis que confieren resistencia a rifampicina e isoniacida detectadas mediante GenoType(r) MTBDR plus V.2 en Colombia / Description of Mycobacterium tuberculosis mutations conferring resistance to rifampicin and isoniazid detected by GenoType(r) MTBDR plus V.2 in Colombia

Resumen Introducción: La metodología de GenoType(r) MTBDRplus V.2 es una técnica molecular aprobada por la Organización Mundial de la Salud y la Organización Panamericana de la Salud para la detección de las mutaciones en el gen rpoβ del complejo Mycobacterium tuberculosis, las cuales confieren resistencia a la rifampicina, y las de los genes katG e inhA que la confieren frente a la isoniacida. Debido a la variación genética en las cepas circulantes a nivel mundial, los programas nacionales de control de la tuberculosis deben comprobar el desempeño de los nuevos métodos de diagnóstico para su aplicación como prueba rápida. Objetivo: Describir las mutaciones detectadas mediante la técnica GenoType(r) MTBDRplus V.2 en muestras pulmonares y aislamientos de M. tuberculosis procesados en el Laboratorio Nacional de Referencia del Instituto Nacional de Salud durante el 2014. Materiales y métodos: Se hizo un estudio retrospectivo descriptivo que determinó la expresión de los genes inhA, KatG y rpoβ responsables de la resistencia a isoniacida y rifampicina, utilizando la técnica GenoType(r) MTBDRplus V.2 en 837 muestras y aislamientos de casos de tuberculosis. Resultados. Se obtuvieron 689 resultados de pruebas: 581(84,3 %) sensibles, 58 (8,4 %) resistentes y 50 (7,2 %) multirresistentes. Se detectaron diversas mutaciones en el gen rpoβ, de las cuales la más frecuente fue la Ser531Leu (36,6 %), seguida por la Asp516Val (21,6 %), en tanto que en el gen katG la más frecuente fue la Ser315Thr1 (91,9 %). Conclusiones: Se detectaron varias mutaciones en los casos resistentes reportados en el país, con frecuencias similares a las reportadas en otros países de la región de América del Sur.

Abstract Introduction: The GenoType(r)MTBDRplusV.2 assay is a molecular technique endorsed by the World Health Organization and the Pan American Health Organization that allows for the identification of the Mycobacterium tuberculosis complex and the detection of mutations in the rpoβ gene for rifampicin resistance, and katG and inhA genes for isoniazid resistance. Due to the genetic variability in the circulating strains around the world, the national tuberculosis control programs should assess the performance of these new diagnostic technologies and their use under program conditions as rapid tests. Objective: To describe the mutations identified by the GenoType(r)MTBDRplusV.2 assay in pulmonary samples and Mycobacterium tuberculosis isolates in the Laboratorio Nacional de Referencia of the Instituto Nacional de Salud in 2014. Materials and methods. We conducted a retrospective, descriptive study to detect the expression of inhA, KatG and rpoβ genes, responsible for resistence against isoniazid and rifampicin using the GenoType(r) MTBDRplus V.2 assay in 837 samples and isolates from tuberculosis cases. Results: Several mutations in the rpoβ gene were identified. Ser531Leu was the most frequent (36.6%) followed by Asp516Val (21.6%), while Ser315Thr1 was the most frequent mutation in the katG gene (91.9%). Conclusions: We were able to identify different mutations present in MDR-TB strains in the country, with frequencies similar to those reported in other countries in the South American region.

Prevalencia de la resistencia de Mycobacterium tuberculosis a quinolonas y fármacos inyectables en Colombia, 2012-2013 / Prevalence of Mycobacterium tuberculosis resistance to quinolones and injectables in Colombia, 2012-2013

Resumen Introducción: La tuberculosis es un problema de salud pública a nivel mundial. En 2014, la Organización Mundial de la Salud estimó que se habían presentado 9,6 millones de casos nuevos y 480.000 multirresistentes. La evaluación de la resistencia a fármacos inyectables y a quinolonas se introdujo hace pocos años, por lo cual no se conoce su prevalencia. Objetivo: Determinar la prevalencia de la resistencia a amicacina, kanamicina, capreomicina y ofloxacina en casos de tuberculosis resistente a isoniacida, rifampicina o a ambas, entre 2012 y 2013. Materiales y métodos: Se hizo un estudio de corte transversal con 489 aislamientos resistentes a isoniacida o rifampicina. Las pruebas de sensibilidad se hicieron con la técnica Bactec MGITTM. Para el análisis de la proporción de la resistencia, los casos se agruparon según el antecedente de tratamiento con medicamentos de segunda línea. Resultados: En los 438 casos nuevos, la resistencia global a la kanamicina fue mayor (7,1 %; IC95% 4,6-9,6); en los 51 casos previamente tratados, dicha resistencia fue de 27,5 % (IC95% 14,2-40,7). La resistencia global fue mayor en casos con antecedentes de tratamiento con quinolonas y fármacos inyectables. Se encontraron siete casos de tuberculosis extremadamente resistente. Conclusión: El estudio evidenció la presencia de resistencia a fármacos de segunda línea en personas con tuberculosis farmacorresistente sin tratamiento previo o tratadas previamente con quinolonas o fármacos inyectables, estos últimos con mayor porcentaje de resistencia. En consecuencia, es esencial practicar rutinariamente las pruebas de sensibilidad y el análisis de esta información.

Abstract Introduction: Tuberculosis is a health problem worldwide. The World Health Organization estimated 9.6 million new cases and 480,000 multirresistant cases for 2014. The assessment of resistance to quinolones and injectables was implemented only a few years ago, so its prevalence is not known. Objective: To determine the prevalence of resistance to amikacin, capreomycin and ofloxacin in cases of tuberculosis resistant to isoniazid and/or rifampin during 2012-2013. Materials and methods: This was a cross-sectional study of 489 isolates resistant to isoniazid and/or rifampin. We used the Bactec MGITTM technique for susceptibility tests. For analyzing the rate of resistance, we grouped cases according to the history of treatment with second line drugs. Results: In the 438 new cases, the drug that showed greater overall resistance was kanamycin with 7.1 % (95% CI: 4.6 to 9.6). In 51 previously treated cases, this highest resistance was 27.5 % (95% CI: 14.2 to 40.7). The overall resistance was higher in cases with a history of treatment with quinolones and injectables. We found seven cases of extremely resistant tuberculosis. Conclusion: This study demonstrates the presence of resistance to second line drugs in people with drug-resistant tuberculosis with and without previous treatment with quinolones and/or injectables, these latter having a higher percentage of resistance. For that reason, it is essential to perform susceptibility testing and analyze this information routinely.

Preparation and antitubercular activity of lipophilic diamines and amino alcohols

A series of diamines and amino alcohols derived from 1-dodecanol, 1-tetradecanol, 1,2-dodecanediol and 1,2-tetradecanediol were synthesized and tested for their antitubercular activity. Compounds 3, 8 and 9 were found to be the most active (MIC of 6.25 µg/mL). Nine other compounds displayed activity against Mycobacterium tuberculosis, with a MIC of 12.5 µg/mL.