Seven-day early bactericidal activity (EBA) of isoniazid (INH). (A) Mean (95% confidence interval) EBA by decrease in colony-forming units (cfu) on solid culture medium, averaged over 7 days, based on log10 cfu count, by arm. (B) Mean (95% confidence interval) EBA based on decrease in time to positivity (TTP) in liquid medium, in hours, averaged over 7 days.