Multilocus sequence typing and phylogenetic analysis
For the S. aureus , S. epidermidis , P. aeruginosa ,
and BCC isolates, we conducted multilocus sequence typing (MLST) by
amplifying seven housekeeping genes using previously described primer
sets (16-19). When aroE of S. aureus was not detected,
alternative primers were used: aroE745-up,
5’-TTATCACCGTCGATGCATAGTGCA-3’; aroE255-down,
5’-CGGAGTAGTATTTATCACAATATC-3’ (20). Furthermore, we used an alternative
forward primer for undetected trpB of BCC: trpE-F2,
5’-AAGGACGCGCTGAACGAAGC-3’. The alternative primers used for the
undetected tpiA of S. epidermidis were as follows: tpi-DF,
5’- GCAAGTATTTGGATAAAAGC-3’; tpi-DR, 5’- CCATCTAAGATGATTAAGGC-3’. The
allele numbers and STs of each isolate were assigned according to the
MLST database (https://pubmlst.org/). We performed advanced cluster
analysis to define clonal complexes (CCs) by using BioNumerics software
ver. 7.6 (Applied Maths, Sint-Martens-Latem, Belgium).