title: Antimicrobial activities of benzylpenicillin in combination with Traditional Herbal Medicines against β-Lactamase-producing bacteria.
abstract: The antibacterial activities of benzylpenicillin (PCG) alone or in combination with herbal medicines, Jyuzen-Taiho-Toh (JTT), Hotyu-Ekki-Toh (HET) and Tohki-Rikuoh-Toh (TRT), were examined against penicillinase (PCase)-producing organisms using an agar dilution method. All of the combinations of PCG and each herbal medicine substantially enhanced the activity of PCG against carbenicillin resistant Pseudomonas aeruginosa PAO2142RP(r)/pMG26: the minimum inhibitory concentration (MIC) value was decreased eightfold. The susceptibility of E. coli strains harboring plasmid encoding PCase, types I, II, and III, respectively, increased slightly to PCG in these combinations, whereas none of these combinations produced the effect in E. coli with type IV PCase. Preincubation of various types of PCase with each herbal medicine induced a reduction in enzymatic activities. The inhibitory activity was found to increase in the following order: TRT < HET < JTT. In the case of JTT, the % inhibitions for types I, II, III, and IV PCase were found to be 104, 100, 97, and 94, respectively. The type I PCase-inhibiting activity of JTT was unaffected by heat treatment at 121°C for 15 min at neutral pH. These results suggested that the combination effect between PCG and herbal medicines might be due to the inhibitory activity of herbal medicines against the PCases.
authors.affiliation: Department of Serology & Microbiology Kanazawa Medical University, Uchinada Kahoku-gun, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Shimizu
authors.forename: H
authors.initials: H
authors.lastname: Furuno
authors.forename: S
authors.initials: S
authors.lastname: Katoh
authors.forename: N
authors.initials: N
authors.lastname: Yamaguchi