A very important aspect of this study
is the increased activity of two-drug combinations containing
pyrazinamide. In two previous EBA studies this
drug had negligible, if any, bactericidal activity in the fi rst
days of treatment.29,31 Similarly, bedaquiline had little
discernible early activity in this and other studies3 but,
with the addition of pyrazinamide, activity occurs much
earlier and at much increased magnitude. Pyrazinamide
also seemed to augment PA-824 activity, which was not
measured in this study but was quantifi ed recently at the
same centres.4,5 With the addition of pyrazinamide the
14-day EBACFU of PA-824 increased from 0·098 to
0·154 and the EBATTP increased from 4·494 to 8·805. In
smaller numbers of patients, Jindani and colleagues29
showed that the EBACFU of pyrazinamide alone during
days 0 to 2 was 0·044, but increased to 0·113 from days 2
to 14. Similar to this study, the addition of pyrazina mide
to isoniazid-streptomycin and isoniazid-rifampicinpyrazinamide
regimens led to a signifi cant improvement
in early activity (p