MPCs and MSWs of S. pneumoniae strains. The horizontal axis represents concentrations of quinolones. Results are shown for the wild-type strains (W001 and W002), the parC single mutation-containing strains (S001 and S002), the gyrA single mutation-containing strains (S003 and S004), and the strains with both parC and gyrA mutations (D001 and D002). The left side, right end, and width of each bar represent the MIC, the MPC, and the MSW, respectively. The lower and higher values in each set of parentheses are quinolone MICs (μg/ml) and MPCs (μg/ml), respectively.