Effects of Cigarette Smoke Condensate on Growth and Biofilm Formation by Mycobacterium tuberculosis

Figure 1

The effect of various concentrations of cigarette smoke condensate (CSC) on biofilm-forming cultures of Mtb. (a) Biofilm was measured using the crystal violet spectrophotometric procedure. (b) Viability of biofilm-forming Mtb was determined using a colony-counting procedure and the results are presented on a linear graph. (c) Measurement of the pH levels of the bacterial growth medium. (d) The effect of catalase (100 mg/L) on biofilm formation by control and CSC-treated Mtb using the crystal violet spectrophotometric procedure. The results of three separate experiments, each with triplicate determinations, are presented as the . (a–c) The black and striped/lined/checkered bars represent the CSC-untreated control (W5) and CSC-treated cultures, respectively, while for (d) the panels on the left (grey columns) and right of each pair (dotted columns) represent catalase-untreated, catalase-treated, CSC-treated cultures, respectively. Statistical significance is represented by an asterisk ( value < 0.05). For (d), represents concentrations of CSC which induced significant increases in biofilm formation in the absence of catalase, while represents significant inhibition of the CSC-mediated increases in biofilm formation in the presence of catalase for each CSC concentration.

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