Fig. 1

Amplification curves (A top) and corresponding melting curve (B bottom). Seven PCR-positive clinical specimens from one patient (numbers correspond to anonymized patient identity) as well as 3 controls (P1, P2 as positive control and negative control) are shown. The yellow curve was clearly PCR-positive but negative by culture. The arrow indicates a positive result as well, the result of which from Sanger sequencing was congruent with other clinical specimens of the same patient. The negative control was flat above 84 °C (marked by black line), which indicates the absence of specific PCR products. Peaks below 84 °C indicate nonspecific amplification (e.g., primer dimers). Different Tm values (above 84 °C) are caused by different sequences (in this case, S. epidermidis has lower Tm, and B. subtilis (present in P1 and P2) has higher Tm