Detalle de: Comment on: Characterization of the embB gene in Mycobacterium tuberculosis isolates from Barcelona and rapid detection of main mutations related to ethambutol resistance using a low-density DNA array

Sir, Whole-genome phylogeny of 219 isolates representative of all major MTBC lineages.9 Glu at codon 378 is a marker for modern MTBC, which all share the TbD1 deletion and include the lineage 4 M. tuberculosis H37Rv laboratory strain that is used as the reference/wild-type sequence for sequence analyses.10 In light of these data, the results of probe 3 would be predicted to lead to systematic false-positive reports, which calls into question the validity of this probe. This underlines that the entire MTBC diversity has to be considered when designing and validating genotypic drug susceptibility testing assays.7,10 This work was supported by a grant from the Department of Health, Wellcome Trust and the Health Innovation Challenge Fund (HICF-T5-342 and WT098600 to S. J. P.), Public Health England (to S. J. P.), the Medical Research Council (to J. M. B.) and the Wellcome Trust Sanger Institute (WT098051 to J. P. and J. M. B). C. U. K. is a Junior Research Fellow at Wolfson College, Cambridge. I. C. is supported by a Ramón y Cajal fellowship from the Spanish Government (RYC-2012-10627). J. P. has received funding for travel and accommodation from Pacific Biosciences Inc. and Illumina Inc. S. J. P. is a consultant for Pfizer Inc. and has received funding for travel and accommodation from Illumina Inc. All other authors: none to declare. This publication presents independent research supported by the Health Innovation Challenge Fund (HICF-T5-342 and WT098600), a parallel funding partnership between the Department of Health and Wellcome Trust. The views expressed in this publication are those of the authors and not necessarily those of the Department of Health or Wellcome Trust.