Then 0 day (Viable count) VC was set up on 7H11 agar plates and the selleckchem drugs were added at different concentrations. Bactericidal action of the drugs PA-824 was injected at two different concentrations of 3 μg/ml (P1), 12.5 μg/ml (P2), and RIF & PZA were injected at 1 μg/ml and 50 μg/ml respectively through the septa of 21-day-old cultures. Culture bottles were prepared in duplicates for each concentration

of the drugs. The culture was removed by means of a syringe through the septa and the VC was set up on 2nd, 4th, 7th, 10th, 14th, and 21st days. The cultures were serially diluted in saline and plated onto 7H11/OADC agar (Difco) plates in duplicates containing polymyxin B (200 U/ml), amphotericin B (20 μg/ml), carbenicillin (100 μg/ml), and trimethoprim (10 μg/ml), to determine colony-forming unit (CFU) counts. The plates were placed in polythene bags, along with a plate inoculated with Mycobacterium phlei and 3-MA purchase incubated at 37°C. M. tuberculosis colonies were counted at 0, 2, 4, 7, 11, 14 and 21 days of incubation. The results were represented, as the mean of the quadruplicates of the cultures for every time point for every drug concentration and for the control cultures it was the Selleck AZD1152-HQPA mean of duplicates (Table 1). Table 1 Bacterial count in Log 10

cfu/ml with standard deviation on different days Days 0 2 4 7 11 14 21 No drug 6.55 ± 0.16 6.68 ± 0.23 6.58 ± 0.13 6.28 ± 0.23 6.35 ± 0.12 6.37 ± 0.09 6.53 ± 0.07 P1 (3 μg/ml) 6.64 ± 0.39 6.45 ± 0.08 6.48 ± 0.22 6.21 ± 0.19 6.20 ± 0.17 5.62 ± 0.54 4.93 ± 0.32 P2 (12.5 μg/ml) 6.67 ± 0.25 5.44 ± 0.44 4.69 ± 0.12 4.18 ± 0.41 4.18 ± 0.51 4.15 ± 0.09 0 RIF (1 μg/ml) 6.93 ± 0.04 6.54 ± 0.13 6.62 ± 0.05 5.2 ± 0.28 5.35 ± 0.06 4.60 ± 0.4 4.59 ± 0.48 PZA (50 μg/ml) 6.08 ± 0.39 6.84 ± 0.02 6.83 ± 0.03 6.30 ± 0.13 6.02 ± 0.44 6.33 ± 0.3 6.49 ± 0.06 Statistics The results were expressed as the mean of the duplicates http://www.selleck.co.jp/products/MLN-2238.html at each time point. Differences in the regression coefficients of the log CFU counts with different drug combinations were tested

by analysis of variance using test command in Stata, release 8 (Stata Corp, College station Tx). The standard deviation (SD) of a result was obtained from the variation between CFU counts on the duplicate cultures, estimated separately for the log phase and the stationary phase cultures. Graphing No adequate representation on a logarithmic axis of the CFU count could be made of counts that yielded no colonies since log 0 is minus infinity. A line was therefore drawn to extrapolate the values obtained at the two previous time points provided that it cut the X axis to the left of the time point yielding no colonies. Otherwise, the line was drawn through Log 0. In each case, the line concerned has been drawn dotted to indicate the uncertainty in its true position.