Screening Bactericidal Action of Cytoplasm Extract from Kumazasa Bamboo (Sasa veitchii) Leaf against Antibiotics- Resistant Pathogens such as MRSA and VRE Strains

We aimed to develop a new treatment against antibiotic-resistant bacteria by focusing on cytoplasm of Kumazasa bamboo leaf. The cytoplasmic extract displays potent bactericidal action against Gram-positive bacteria such as Staphylococcus aureus, Enterococci and Streptococcus pneumoniae and also multi-antibiotic resistant MRSA (methicillin-resistant Staphylococcus aureus) and VRE (vancomycin-resistant Enterococci) strains. It induced bacteriolysis by firmly aggregating MSSA (methicillin-susceptible Staphylococcus aureus) and MRSA, and by lysis of VSE (vancomycin-susceptible Enterococci) and VRE. Clinical isolates of MRSA (30 strains in total) were susceptible to this extract, which gave MICs of Kumazasa-cytoplasmic extract ranging from 1.6 to 6.3%. The antibacterial action was bactericidal on scanning electron microscopy (SEM) analysis. A synergistic effect of this extract with ampicillin (ABPC) was obviously observed in all MRSA strains. The synergistic effect with vancomycin (VCM) was observed against VRE. The combination with clarithromycin (CAM) or tetracycline (TC) additively enhanced the antibacterial activity of CAM against CAM-susceptible Enterococci strains, and also that of TC against TC-resistant VRE strains.