%0 Journal Article
%T Association between embB mutations and ethambutol resistance in Mycobacterium tuberculosis isolates from Cuba and the Dominican Republic: reproducible patterns and problems Asociaci¨®n entre las mutaciones en embB y la resistencia a etambutol en aislamientos de Mycobacterium tuberculosis de Cuba y Rep¨²blica Dominicana: patrones y problemas reproducibles
%A Elba Guerrero
%A Dihadenys Lemus
%A Sergio Yzquierdo
%A Glenda V¨ªlchez
%J Revista argentina de microbiolog£¿-a
%D 2013
%I Asociaci¨®n Argentina de Microbiolog¨ªa
%X The relation of ethambutol resistance to embB mutations remains unclear, and there are no reports on ethambutol resistance from the Caribbean. We examined the sequence of embB in 57 distinct Multi-Drug Resistant (MDR) and non-MDR strains of Mycobacterium tuberculosis, mostly from Cuba and the Dominican Republic. embB306 codon mutations were found exclusively in MDR-TB, but in both ethambutol sensitive and resistant strains. Valine substitutions predominated in ethambutol resistant strains, while isoleucine replacements were more common in sensitive strains. Three ethambutol resistant MDR strains without embB306 substitutions had replacements in embB406 or embB497, but these were also found in ethambutol sensitive MDR strains. The results confirm previous findings that amino acid substitutions in EmbB306, EmbB406 and EmbB497 are found only in MDR-TB strains but in both phenotypically resistant and sensitive strains. One ethambutol resistant non-MDR strain did not have any embB mutation suggesting that other undefined mutations can also confer ethambutol resistance. La relaci¨®n entre resistencia a etambutol y mutaciones en embB no se ha establecido claramente y no existen comunicaciones sobre la resistencia a etambutol en cepas provenientes de pa¨ªses Caribe os. Se evalu¨® la secuencia del gen embB en 57 cepas de Mycobacterium tuberculosis multi-drogo resistentes (MDR) y no-MDR, la mayor¨ªa aislada en Cuba y Rep¨²blica Dominicana. Se encontraron mutaciones en el cod¨®n embB306 exclusivamente en cepas MDR, tanto en cepas sensibles como resistentes a etambutol. Tres cepas MDR resistentes a etambutol, sin sustituciones en embB306, ten¨ªan mutaciones en los codones embB406 o embB497, pero estos cambios se encontraron tambi¨¦n en cepas sensibles. Los resultados confirman otros estudios, mostrando que sustituciones aminoac¨ªdicas en EmbB306, EmbB406 y EmbB497 se encuentran exclusivamente en cepas MDR, tanto resistentes como sensibles a etambutol. Encontramos una cepa no MDR resistente a etambutol sin ninguna mutaci¨®n en embB, sugiriendo que otras mutaciones a¨²n no identificadas tambi¨¦n pueden conferir resistencia a etambutol.
%K Mycobacterium tuberculosis
%K Resistencia a etambutol
%K Multi-drogo resistencia
%K Mutaciones en embB
%K Prueba de sensibilidad
%K Mycobacterium tuberculosis
%K Ethambutol resistance
%K Multidrug resistance
%K embB mutations
%K Drug sensitivity testing
%U http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S0325-75412013000100004