FIGURE 4.

Microcalorimetry analysis of (A,B) mono- and (C) dual-species MRSA (ATCC 43300) and P. aeruginosa (ATCC 27853) biofilms treated with two-fold increasing concentrations of ciprofloxacin (left column, numbers represent concentrations in mg/L of antibiotic) or with phages (right column). Each curve shows the heat produced by viable bacteria present in the biofilm after 24 h of antibiotic or phage treatment. A circled value represents the MBEC, defined as the lowest concentration of antibiotic that strongly reduced the viability of biofilm cells leading to the absence of heat flow production from treated beads when incubated during 48 h in fresh medium and no colonies after sonication and plating. GC, growth control (dashed line); NC, negative control. Data of a representative experiment are reported.