NAC inhibits the growth of hypervirulent Beijing strain in vitro. Beijing 1471 M. tuberculosis strain was grown in Middlebrook 7H9 supplemented with OADC with or without NAC (10 mM). CFU counts were performed as described in Methods. Significant differences were observed for the indicated experimental conditions compared to untreated cultures. The data represent the means ± SEM from two independent experiments. (**p