One hundred microliters of each bacterial inoculum, standardized according to 1 McFarland turbidity and diluted 1:20 in Middlebrook 7H9 medium supplemented with OADC, was inoculated into the wells containing media. A growth control containing no drug and a sterile control without bacteria were also prepared for each assay. The plates were covered with their lids and their edges sealed with polyethylene tape. The plates were placed in a plastic box and incubated at 35 8C at normal atmosphere for 7 days.