Antibacterial properties of Chinese herbal medicines against nosocomial antibiotic resistant strains of Pseudomonas aeruginosa in Taiwan

• Published in: The American journal of Chinese medicine (1979) Vol. 35; no. 6; p. 1047
• Main Authors: Liu, Ching-Shen, Cham, Thau-Ming, Yang, Cheng-Hong, Chang, Hsueh-Wei, Chen, Chia-Hong, Chuang, Li-Yeh
• Format: Journal Article
• Language: English
• Published: Singapore 2007
• Subjects: Animals; Anti-Bacterial Agents - pharmacology; Anti-Bacterial Agents - therapeutic use; Cross Infection - drug therapy; Cross Infection - transmission; Dose-Response Relationship, Drug; Drug Resistance, Bacterial - drug effects; Drug Resistance, Bacterial - genetics; Drug Synergism; Drugs, Chinese Herbal - pharmacology; Drugs, Chinese Herbal - therapeutic use; Humans; Pseudomonas aeruginosa - drug effects; Pseudomonas aeruginosa - genetics; Pseudomonas Infections - drug therapy; Pseudomonas Infections - transmission; Taiwan; Taiwan
• ISSN: 0192-415X
• DOI: 10.1142/S0192415X07005508

Pseudomonas aeruginosa is well-recognized as a nosocomial pathogen, which exhibits inherent drug resistance. In this study, the antibacterial activity of ethanol extracts of 58 Chinese herbal medicines used in Taiwan were tested against 89 nosocomial antibiotic resistant strains of Pseudomonas aeruginosa. The results gathered by the disc diffusion method showed that 26 out of the 58 herbal extracts exhibited antibacterial activity. Among the 26 herbal extracts, 10 extracts showed broad-spectrum antibacterial activities and were selected for further antibacterial property assay. The minimum inhibitory concentrations (MIC) of the active partition fractions ranged from 0.25 to 11.0 mg/L. The presence of flavonoid compounds in the active fractions of test herbal extracts was observed by the TLC-bioautography. The results from the time-kill assay revealed that most of the herbal extracts completely killed the test organisms within 4 hours. Exposure of the test strains to a sub-MIC level of the herbal extracts for 10 consecutive subcultures did not induce resistance to the active components. A combination of the active herbal fractions with antibiotics showed that one of the herbal medicines, the hexane fraction of Ramulus Cinnamomi, possessed a synergistic effect with tetracycline, gentamycin, and streptomycin. In conclusion, the tested Chinese medical herbs have the potential to be developed into natural antibiotics. This is the first evaluation for screening large amounts of medical plants against nosocomial antibiotic resistant bacteria in Taiwan.