Table 1.
Bacterial strains and plasmids used in this study.
Table 2.
Primers for sequencing and cloning of mprF gene.
Fig 1.
POT analysis for genotyping of each strain.
Clinical isolates KAM17 and KAM18 had the same POT pattern. Manipulated strains KAM17mut and KAM17mutR also had the same POT pattern as KAM17. The band of 355 bp in mixture 1 was SCCmec type II specific.
Fig 2.
Sequence analysis of the mprF gene in each strain.
The 1034th cytosine was changed to thymine in KAM18 causing a missense mutation, which resulted in T345I amino acid substitution. N315 was used as a reference sequence of mprF.
Table 3.
MICs of each strain by E-test.
Fig 3.
Population analysis of each strain for DAP susceptibility.
The number of colonies developed on the plates containing various concentrations of DAP was counted. The data shown are representative of two independent experiments with similar results.
Fig 4.
Cytochrome c binding assay of each strain.
Each strain was incubated with cytochrome c. The adsorbed cytochrome c was calculated by the residual cytochrome c in the supernatant. The error bars indicate standard error from six independent experiments (** p < 0.01).
Fig 5.
(A) The concentration of bacteria was measured as the optical density at 660 nm. MprF mutant DAP resistant strain KAM18 and KAM17mut grew slower than DAP susceptible strains, KAM17 and KAM17mutR. The growth curves are representative of three independent experiments with similar results. (B) The doubling time of each strain was calculated according to its regression curve. The calculated values represent mean ± SD of three independent experiments (**p<0.01 vs. KAM17).
Fig 6.
Transmission electron microscopy images of each strain.
(A) Cell wall thickness was measured at 200,000× magnification. Fifty measurements were obtained, and the results are expressed as mean ± SDs (**p<0.01 vs. KAM17).