Plasmid Curing Activity of Five Plant Extracts on Multiple Resistant Plasmid Bearing Klebsiella Pnumoniae Strains

ABSTRACT The curing of five medicinal plant extracts (Satureia hortensis, Glycyrrhiza glabra, Teucrium Pollium, Myrtus Communis, Eukalypetus globolus) on plasmid bearing strains of klebsilla pnenmoniae resistance to multiple antibiotics were investigated. Alcoholic and maceration extraction were carried out from leaves, fruits or roots of the above plants. Mimimum inhibitory concentrations (MIC) of each plant extract indicated that all of them have antimicrobial activity and were able to inhibit the growth of resistant strains of kleb. pneumoniae. Furthermore the eucalypetus extract had highest antimicrobial activity as compared to other plant extracts (avrage MIC 0.1mg/ml). At the same time the subinhibitory concentration (SIC) and minimum bactricidal conctration (MBC) activity of each plant extract was carried out in order to cure plasmids from plasmid bearing strains. Curing experiments were performed from SIC tubes which then diluted serially (10-2, 10-4,10-6,10-8)and 100 well isolated colonies were then master plated with sterile tooth pikes. The sensitivity of the strains treated with SIC of each plant extracts to ampicillin amoxicillin, cefotaxime,and ceftizoxime indicated that there were no change in MIC of antibiotics compared to unexposed one. The morphological investigation with flouresent microscope (Nikon, optiphota-2) and capsule staining indicated that when cells treated with Myrtus Communis extract, the cells aggregated and change their morphology, similarly, production of cupsule was also lost. The agarose gel electrophoresis (0.7%) of the treated cells and untreated one and observation of the gel with U.V. gel documentation system indicated that there were any physical loss of plasmid band on the gel. Similarly, the synergistic action of plant extract and antibiotics were investigated and it was found that these was no synergy between the above plant extracts and antibiotics (MIC remained unchanged). From above data it could be concluded that the above plants extract though they have antibacterial activity they didnot exert any curing effect on the plasmid bearing microoganisms isolated from hospitals in kerman Iran.