Isoniazid-resistant mutants of Mycobacterium tuberculosis H 37 RV: uptake of isoniazid and the properties of NADase inhibitor

Abstract

Six independent isoniazid-resistant mutants of Mycobacterium tuberculosis were isolated under conditions which largely ensured the selection of one-step mutants. The properties of these mutants with respect to the nicotinamide adenine dinucleotide nucleosidase (NADase) inhibitor, isoniazid uptake and peroxidase activity were studied. The uptake of isoniazid by the mutants and their sensitivity to isoniazid were increased by ethylenediaminetetra-acetic acid (EDTA) and sodium dodecylsulphate. It is suggested that EDTA and sodium dodecylsulphate bring about these effects by altering the cell permeability.