Biofilm Formation Genes in S. aureus

The expression of adhesion and biofilm formation genes in ST188 was detected by RT-PCR. We chose ST398 as the reference group because ST398 is an important host-species-adaptable S. aureus lineage with high virulence but low biofilm formation ability^{18 (link),21 (link)}. Complementary DNA was synthesized from total RNA using the QuantiTect reverse transcription system (Qiagen) according to the manufacturer’s instructions. Complementary DNA samples were amplified using the QuantiTect SYBR green PCR kit (Qiagen). Reactions were performed using a 7500 Sequence Detector (Applied Biosystems). We used purified chromosomal DNA at concentrations of 0.005–50 ng/ml to form a standard curve. All quantitative reverse-transcription polymerase chain reaction (qRT-PCR) experiments were performed in duplicate with gyrB as a control.