Figure 4. Percentage of planktonic and sessile cells in single and dual cultures.

Bacteria were grown overnight in 96-well flat-bottom microtiter plates in NB medium at 37°C either individually cultured or co-cultured at a 1∶1 ratio. CFU counts were determined in both planktonic and sessile fractions and the percentage of S. aureus and P. aeruginosa in the two fractions of single and dual cultures was calculated. Panel A: percentages of planktonic and sessile cells of Newman in single culture (first histogram), PA14 in single culture (second histogram), Newman and PA14 in ideal co-culture if the 2 species would not interfere each other (third histogram, percentages have been calculated considering the values of the first and second histograms), and Newman and PA14 in co-culture (fourth histogram). Panel B: percentages of planktonic and sessile cells of Newman in single culture (first histogram), AA2 in single culture (second histogram), Newman and AA2 in ideal co-culture if the 2 species would not interfere each other (third histogram, percentages have been calculated considering the values of the first and second histograms), and Newman and AA2 in co-culture (fourth histogram). Panel C: percentages of planktonic and sessile cells of Newman in single culture (first histogram), AA43 in single culture (second histogram), Newman and AA43 in ideal co-culture if the 2 species would not interfere each other (third histogram, percentages have been calculated considering the values of the first and second histograms), and Newman and AA43 in co-culture (fourth histogram). SA: S. aureus; PA: P. aeruginosa.