Table 1

Pyrazinamide MICs in Bactec MGIT 960 system correlated to pncA gene sequencing data and previously obtained Bactec 460 results for 46 M. tuberculosis strains

Strain groupMGIT PZA MIC (mg/liter)No. of strainspncA amino acid changePrevious BACTEC 460 resultc
PZAINHRIFEMBSM
Consecutive fully susceptible strains≤81NoneSSSSS
164NoneSSSSS
328NoneSSSSS
642NoneSSSSS
Nonconsecutive strains with MICs less than or equal to ECOFF (≤64 mg/liter)161NoneSSSSS
322NoneSSSSS
321NoneSSRSS
321aSer65SerSRRSS
643NoneSSSSS
641NoneRRSSR
641NoneSRSSS
641aThr47AlaRRRRR
Nonconsecutive strains with MICs greater than ECOFF (>64 mg/liter)1281aNoneSSSSS
1281bPhe58LeuRRRSS
2561aNoneRRRRR
2561Ser65Ser/frameshiftRRRSS
2561Ile6ThrRRRRS
2561Val125PheRRRSS
5121Pro54LeuRRRSS
5121Phe58LeuRRRSR
1,0241Gly132AlaRRRRR
1,0241Leu172ProRRRRS
1,0241Val155GlyRRRSR
>1,0241Val155GlyRRRSS
>1,0241Met175ThrRRRRR
>1,0241Pro54SerRRRRS
>1,0241Gly132SerRRRRS
>1,0241FrameshiftRRRSR
>1,0241bHis51GlnRSSSS
>1,0241Arg123ProRSSSS
>1,02414-amino-acid in-frame insertionRRRSS
>1,0241Thr142LysRRRRS
  • a PZase positive.

  • b PZase negative.

  • c INH, isoniazid (0.1 mg/liter); RIF, rifampin (1 mg/liter); EMB, ethambutol (2.5 mg/liter); SM, streptomycin (1 mg/liter); PZA, pyrazinamide (100 mg/liter); R, resistant; S, susceptible.