Antibacterial Activity of DMSO Extracts of Selected Plants Against Antibiotic Resistant Clinical Isolates

In this study, we aimed to find out new herbal materials that are able to inhibit the growth of the P. aeruginosaand E.coli clinical isolates that has antibiotic resistance. Clinical isolates used in this research are E. coli (n=1)and P.aeruginosa (n=1). Antibiotic susceptibility profiles of E. coli and P. aeruginosa were determined usinge-test. Plants were collected in Trabzon region of Turkey are Calendula officinalis, Hypericum perforatum andGlycyrrhiza glabra. DMSO were used as solvent and solid-liquid extraction was employed. Micro-dilutionmethod was preferred fo the determination of the minimum inhibitory concentration (MIC). MIC results wereobtained through observation of turbidities. According to E-test results, while P. aeruginosa was resistant topiperacillin, piperacillin/tazobactam, meropenem and ceftazidime, E. coli was resistant to piperacillin,cefotaxime and ceftazidime. DMSO extract of Calendula officinalis showed very strong activity against PA1with the best MIC (5 mg/mL). DMSO extract of three plant had lower MIC values (5-10 mg/ml) for EC1 andPA1 than ampicillin. In future studies antibacterial activity of different solvents extracts of these plants andother plants against antibiotic resistant clinical isolates will be examined. Natural products from plants arepromising in fighting with antibiotic-resistant bacteria.