Figure 1

A: Three sizes of diameter punch (0.5-mm, 1-mm, 2-mm) involving higher and lower bacteria concentrations for PCR. −6 stands for 60 CFU ml−1, −1 stands for 6×106 CFU ml−1; B: Standard curve of real-time quantitative PCR of 6 decimal dilutions of representative Staphylococcus aureus ranging from 6×104 to 6×109 CFU ml−1.