2.3 DNA extraction
Each fecal specimen was centrifuged at 1,500xg for 10 min at room temperature, followed by isolation of genomic DNA from each sample (~200 mg) using QIAamp DNA Mini Stool Kit (Qiagen, Germany) following manufacturer’s instructions. The lysis temperature was raised to 95°C to obtain higher yield. AE elution buffer (200 mL) was used to elute the DNA, followed by storage at -20°C for further PCR analysis.