96 spot polished steel target plate

Mass spectra were generated using a MALDI Biotyper 3.0 Ultraflex platform (Bruker Daltonics, Massachusetts, USA). For individual suspected S. argenteus isolates, with white colonies, 1 ml of crude protein extract or one colony was deposited on a 96‐spot polished steel target plate (Bruker Daltonics), air‐dried and covered with 1 ml of HCCA matrix solution (Bruker Daltonics) (Kolecka et al., 2013). As a positive control and calibration reference, 1 ml of Bacterial Test Standard (Bruker Daltonics) was used. The main spectrum was acquired using the MALDI Biotyper Automated Flex Control software v.3.0 (Bruker Daltonics). The identification of isolates was performed using the Bruker database and in‐house databases from Chantratita et al. (2016) and Moradigaravand et al. (2017).

Upon signaling positive, the blood culture broth was analyzed by Gram stain and cultured onto a blood agar plate (BIOIVT, Zhengzhou, China) and/or obligate anaerobic agar plate (BIOIVT, Zhengzhou, China), and incubated in 5%CO₂ at 35 ± 1°C for 18 to 24 h (Thermo Fisher Scientific, USA). Whenever Gram stain indicated the presence of fungi, the sample was additionally subcultured on SDA agar plate (BIOIVT, Zhengzhou, China) and incubated at 37°C for 48 h. Following incubation, a sterile, disposable inoculation loop was used to transfer sufficient colonies of a pure culture from those subculture media to a 96-spot polished steel target plate (Bruker Daltonics, Bremen, Germany) for MALDI-TOF MS analysis.