Transformation with KatG Restores Isoniazid-sensitivity in Mycobacterium Tuberculosis Isolates Resistant to a Range of Drug Concentrations

Isoniazid-resistant isolates of Mycobacterium tuberculosis were transformed with a plasmid vector carrying the functional catalase-peroxidase (katG) gene. Expression of katG restored full drug susceptibility in isolates initially resistant to concentrations ranging from 3.2 to > 50 micrograms ml-1. Transformation with the corresponding katG gene from Escherichia coli resulted in low-level expression of catalase and peroxidase activities and conferred partial isoniazid sensitivity.