title: Blepharismin produced by a protozoan Blepharisma functions as an antibiotic effective against methicillin-resistant Staphylococcus aureus.
abstract: A ciliated protozoan, Blepharisma japonicum, produces a photosensitive red pigment, blepharismin (BLR). This study showed that the pigment inhibits the growth of Gram-positive bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA) resistant to arbekacin (ABK), which is the most effective aminoglycoside antibiotic against MRSA and used world wide. Although the minimum inhibitory concentration (MIC) of BLR to the ABK-resistant MRSA strain was 6.25 micrograms/ml in dark, it was decreased to 1.25 micrograms/ml by irradiation with white light of 65 W/m2 for 30 min, suggesting that the antibacterial activity of BLR is photoactivated. Our findings suggested that the antibacterial activity of BLR in dark is due to inhibition of protein synthesis. In addition, we found that BLR is bactericidal and enhances synergistically the antibacterial activity of ABK.
authors.affiliation: Institute of Pharmaceutical Sciences, Hiroshima University School of Medicine, Japan.
authors.forename: B
authors.initials: B
authors.lastname: Pant
authors.forename: Y
authors.initials: Y
authors.lastname: Kato
authors.forename: T
authors.initials: T
authors.lastname: Kumagai
authors.forename: T
authors.initials: T
authors.lastname: Matsuoka
authors.forename: M
authors.initials: M
authors.lastname: Sugiyama
mesh_terms: D000617:Aminoglycosides; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000096:biosynthesis* / Q000494:pharmacology* / Q000528:radiation effects; D016798:Ciliophora / Q000378:metabolism*; D003982:Dibekacin / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology; D004357:Drug Synergism; D016106:Methicillin Resistance; D010569:Perylene / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology / Q000528:radiation effects; D010777:Photochemistry; D010860:Pigments, Biological / Q000096:biosynthesis / Q000494:pharmacology* / Q000528:radiation effects; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000528:radiation effects
chemical_list: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D010860:Pigments, Biological; C092293:blepharismin; D003982:Dibekacin; D010569:Perylene; C031986:arbekacin