Comparison of pyrazinamide drug susceptibility of m.tuberculosis by radiometric bactec and enzymatic pyrazinamidase assay

The aim of this study was to perform pyrazinamide (PZA) susceptibility testing of M.tuberculosis by enzymatic PZA assay and compare the results with radiometric BACTEC 460 TB system and LJ proportion method. One hundred and thirty clinical isolates of M.tuberculosis were included in the study. Of the 130 clinical isolates tested, five were resistant and 124 were sensitive by both methods thus giving overall sensitivity and specificity of 83.33% and 100% respectively. Concordance was found in 129 out of 130 strains tested by all three methods. Pyrazinamidase assay can be used as an alternative to BACTEC and LJ proportion method.