IADR Abstract Archives
Antibacterial activity of probiotics candidate Lactobacillus gasseri against methicillin-resistant Staphylococcus aureus
Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) is a causative bacterium for ventilator-associated pneumonia (VAP), which develops 48 hours after beginning of artificial respiration under tracheal intubation. Perioperative management such as prevention by oral care and hand finger disinfection and postoperative management such as antibacterial agent administration are currently conducted, but additional application of probiotics expected to improve the microflora will lead to further reduction of risks. The purpose of this study was to verify growth suppression of MRSA involved in severe VAP using probiotic candidate Lactobacillus gasseri in the oral cavity area.
Methods: L. gasseri YIT 12321 and MRSA JCM 8702 were used as test bacteria. L. gasseri was cultured in Lactobacilli MRS medium and MRSA was cultured in TS medium anaerobically at 37 ° C for 18 hours. In competition assay, a 1: 1 mixed agar medium of Lactobacilli MRS medium and TS medium was prepared, 5 μl of cultured bacterial suspension of both bacteria was inoculated at 6 mm intervals on mixed agar medium, and then anaerobically cultured at 37 ° C. The antibacterial activity of L. gasseri against MRSA was examined using radial diffusion assay. A fraction obtained by 50% saturated ammonium sulfate precipitation was examined by SDS-polyacrylamide gel electrophoresis (PAGE).
Results: In competition assay, proliferation inhibition of MRSA by L. gasseri was observed. Moreover, it was confirmed that the growth of MRSA was inhibited by neutralized culture supernatant of L. gasseri in radial diffusion assay suggesting that the growth of MRSA was suppressed by the antibacterial substance produced by L. gasseri and that L.gasseri will be expected as a candidate of probiotics.
Conclusions: L. gasseri is a probiotic candidate bacterium having a bacteriocin-like substance which enables growth suppression of MRSA.
Methods: L. gasseri YIT 12321 and MRSA JCM 8702 were used as test bacteria. L. gasseri was cultured in Lactobacilli MRS medium and MRSA was cultured in TS medium anaerobically at 37 ° C for 18 hours. In competition assay, a 1: 1 mixed agar medium of Lactobacilli MRS medium and TS medium was prepared, 5 μl of cultured bacterial suspension of both bacteria was inoculated at 6 mm intervals on mixed agar medium, and then anaerobically cultured at 37 ° C. The antibacterial activity of L. gasseri against MRSA was examined using radial diffusion assay. A fraction obtained by 50% saturated ammonium sulfate precipitation was examined by SDS-polyacrylamide gel electrophoresis (PAGE).
Results: In competition assay, proliferation inhibition of MRSA by L. gasseri was observed. Moreover, it was confirmed that the growth of MRSA was inhibited by neutralized culture supernatant of L. gasseri in radial diffusion assay suggesting that the growth of MRSA was suppressed by the antibacterial substance produced by L. gasseri and that L.gasseri will be expected as a candidate of probiotics.
Conclusions: L. gasseri is a probiotic candidate bacterium having a bacteriocin-like substance which enables growth suppression of MRSA.