Genomic and plasmid DNA were extracted from 20 pathogenic
strains by TIANamp Bacteria DNA Kit (Tiangen Biotech Beijing Co.,
Ltd., China) and TIANprep Mini Plasmid Kit (Tiangen Biotech Beijing
Co., Ltd., China) respectively according to the manufacturer's instructions
and stored at 20 C prior to PCR analysis. PCR detection
assays were used to determine the presence or absence of 38 ARGs
belonging to 6 classes. Primers of all target ARGs were synthesized
based on the published literature, with details listed and described
in Table S2. PCR fragments were sequenced for both strands by
Sangon Biotech (Sangon Biotech, Shanghai) and analyzed with the
BLAST program (http://www.ncbi.nlm.nih.gov/BLAST).