Antibacterial properties of Chinese herbal medicines against nosocomial antibiotic resistant strains of Pseudomonas aeruginosa in Taiwan.
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.
Liu
Ching-Shen
CS
Graduate Institute of Pharmaceutical Sciences, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
Cham
Thau-Ming
TM
Yang
Cheng-Hong
CH
Chang
Hsueh-Wei
HW
Chen
Chia-Hong
CH
Chuang
Li-Yeh
LY
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D003428:Cross Infection / Q000188:drug therapy / Q000635:transmission; D004305:Dose-Response Relationship, Drug; D024881:Drug Resistance, Bacterial / Q000187:drug effects* / Q000235:genetics; D004357:Drug Synergism; D004365:Drugs, Chinese Herbal / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D011552:Pseudomonas Infections / Q000188:drug therapy / Q000635:transmission; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000235:genetics; D013624:Taiwan
D000900:Anti-Bacterial Agents; D004365:Drugs, Chinese Herbal