Genomic DNA extraction of cells was prepared as follows: the bacterial pellets were resuspended in 180 mL of enzymatic lysisbuffer containing Tris (20 mM), Na2-EDTA (2 mM), TritonX-100 (1.2%), and lysozyme (20 mg/mL) and incubated at 37 C for 30 min. Subsequently, bacterial DNA was extracted using DNeasy blood and tissue kit (Qiagen, Hilden, Germany) according to the manufacturer's instructions. The extracted genomic DNA was used in mPCR assay immediately.