ABSTRACT
A new mutation in mabA, Thr4Ile, was identified in a Mycobacterium tuberculosis isolate from a patient whose culture remained positive after treatment. The same mutation was found in another 5 patients infected by different strains. A putative role for this mutation in the process of diminishing susceptibility to isoniazid is evaluated.
Subject(s)
3-Oxoacyl-(Acyl-Carrier-Protein) Reductase/genetics , Antitubercular Agents/pharmacology , Isoniazid/pharmacology , Mutation , Mycobacterium tuberculosis/genetics , 3-Oxoacyl-(Acyl-Carrier-Protein) Reductase/physiology , Antitubercular Agents/therapeutic use , Base Sequence , Drug Resistance, Bacterial/genetics , Humans , Isoniazid/therapeutic use , Male , Microbial Sensitivity Tests/methods , Middle Aged , Molecular Sequence Data , Mycobacterium tuberculosis/drug effects , Mycobacterium tuberculosis/enzymology , Sequence Alignment , Tuberculosis, Pulmonary/drug therapy , Tuberculosis, Pulmonary/microbiologyABSTRACT
Our study provides an alert regarding the transmission of rifampin-susceptible strains of Mycobacterium tuberculosis with a silent substitution in codon 514 of rpoB. Among 1,450 cases, we identified 12 isolates sharing this mutation and related restriction fragment length polymorphism (RFLP) types. The mutation impaired hybridization with the wild-type probes in three independent commercial assays, which could lead to misassignment of resistance.
