Atcc 6919

The P. acnes isolate was obtained from the American Type Culture Collection (ATCC® 6919™). The strain was streaked from freezer stock onto Tryptic soy agar plates (TSA) supplemented with 5% sheep blood (BD, Franklin Lakes, NJ) and incubated at 37°C for 72 h prior to making liquid cultures in brain heart infusion (BHI) broth (BD, Franklin Lakes, NJ) supplemented with 1% dextrose (Fisher Scientific, Waltham, MA) (additional 72 h incubation) for use in the below described assays. All cultures were grown in anaerobic chambers using the EZ Anaerobe Chamber (BD, Franklin Lakes, NJ) and GasPak EZ Anaerobe container sachets (BD, Franklin Lakes, NJ).

C. acnes standard strain ATCC 6919 was obtained from the American Type Culture Collection (ATCC) (Manassas, VA, USA), while S. epidermidis DSM 28319 (equivalent to ATCC 35984) was obtained from the German Collection of Microorganisms (Braunschweig, Germany). C. acnes was cultured anaerobically on RCM agar (Oxoid Limited, Basingstoke, United Kingdom (UK) and incubated for 48 h at 37 °C under ~5% CO₂ using an anaerobic jar and anaerobic atmosphere generation bags (Sigma–Aldrich, St. Louis, MO, USA). Isolated colonies of C. acnes were sub-cultured in an RCM broth for 48 h at 37 °C under anaerobic conditions. For S. epidermidis, the bacteria were cultured aerobically on brain heart infusion (BHI) agar (LAB M limited, Lancashire, UK) and incubated at 37 °C for 18 h. Isolated colonies of S. epidermidis were sub-cultured in BHI broth and incubated at 37 °C for 18 h aerobically. Glycerol stock of each bacterial strain were prepared using their appropriate media supplemented with 25% glycerol and stored in a −70 °C freezer (Thermo Fisher Scientific, Waltham, MA, USA).

Samples of kimchi soup were used to inoculated de Man-Rogosa-Sharpe (MRS) agar plate medium (cat. No.: HB0384, Hope Bio-Technology Co., Ltd) and incubated under aerobic conditions at 37°C for 72 h (31 (link)). A lactic acid bacterium was isolated and designated as L. plantarum VHProbi^® E15 based on polyphasic analysis (32 (link)). C. acnes ATCC 11827 and ATCC 6919 were purchased from American Type Culture Collection, (Manassas, VA, USA). C. acnes ATCC 11827 and ATCC 6919 were maintained on a Reinforced Clostridial Medium (RCM, cat. no.: HB0316, Hope Bio-Technology Co., Ltd) and incubated in an anaerobic jar (Sigma-Aldrich^®) with an oxygen absorber CO₂ generator (AnaeroPack C-1, MGC^®, Japan) at 37°C for 48 h.