Effects of extracts from lichen Ramalina pacifica against clinically infectious bacteria

Abstract

Bactericidal activity of crude extracts from lichen Ramalina pacifica were screened against 20 clinical pathogenic strains isolated from different infectious sources which belong to Pseudomonas aeruginosa, Klebsiella pneumonia, Salmonella typhi, Salmonella paratyphi, Echerichia coli, and Staphylococcus aureus. The minimal inhibitory concentration of petroleum ether extract and ethanol extract was determined against AmericanTypeCellCulture and MicrobialTypeCellCulture strains. Both the extracts exhibited predominant antibacterial activity against all the multi-resistant strains isolated from infected patient’s sample with significant zone of inhibition at MIC=100μg/100μL. The bactericidal activity was assessed comparatively with the reference ATCC strains (Pseudomonas aeruginosa- ATCC-20852; Staphylococcus aureus- ATCC 29737), (Salmonella typhi – ATCC-19430), (Salmonella paratyphi – ATCC-9150), (E. coli – ATCC-25922) and MTCC strains (Klebsiella pneumoniae – MTCC-618) respectively. Ciproflaxin at the concentration 50μg/100μL was used as standard. Ethanolic extract exhibited significant zone of inhibition against the clinical strains of S. aureus (16.67±1.05mm) and E. coli (17.00±1.24mm) isolated form the abscess and hospital effluent respectively. The results were promising and supported the traditional use of lichens for the treatment of respiratory infections, urinary tract infections and pneumonia. [Researcher. 2010;2(3):81-85]. (ISSN: 1553-9865).