SAMN
DNA from different samples was extracted using The E.Z.N.A. Stool DNA Kit (D4015-02, Omega, Inc., USA) according to manufacturers instructions. The reagent which was designed to uncover DNA from trace amounts of sample has been shown to be effective for the preparation of DNA of most bacteria. Sample blanks consisted of unused swabs processed through DNAextraction and tested to contain no DNA amplicons. The total DNA was eluted in 50 l of Elution buffer by a modification of the procedure de-scribed by manufacturer (QIAGEN) and stored at -80C until measurement in the PCR by LC-BIO TECHNOLOGIES (HANGZHOU) CO., LTD., Hang Zhou, Zhejiang Province, China.