Probiotic potential of Staphylococcus hominis MBBL 2-9 as anti-Staphylococcus aureus agent isolated from the vaginal microbiota of a healthy woman

To isolate and characterize an antagonist for use as probiotic agent in the biocontrol of Staphylococcus aureus. Bacteria that exhibited antimicrobial activity against Gram-positive bacteria including Staph. aureus were isolated from 12 healthy women, with Staphylococcus hominis MBBL 2-9 showing the strongest activity. The bacteriocin produced by Staph. hominis MBBL 2-9 was purified by 60% ammonium sulfate saturation, ultrafiltration, HLB cartridge and reverse-phase HPLC. The molecular weight was estimated as 2038·2 Da by MALDI-TOF mass spectrometry. The antagonist survived up to 2 h in artificial gastric juice (pH 2·5) and grew in the presence of 1% porcine bile extract. In addition, Staph. hominis MBBL 2-9 adhered effectively to HT-29 epithelial cell line. Staphylococcus hominis MBBL 2-9 exhibited desirable probiotic traits such as acid tolerance, bile resistance and adherence to epithelial cell line. The bacterium also produced a bacteriocin with unique molecular weight and high antimicrobial activity similar to traditional antibiotics. This study is the first report of a bacteriocin-producing Staph. hominis MBBL 2-9 that has potential for use as a probiotic agent against Staph. aureus.