Antibacterial Activity of Essential Oil of Sature jahortensis Against Multi-Drug Resistant Bacteria

Development of resistance to many of the commonly used antibiotics is an impetus for further attempts to search for new antimicrobial agents. In the present study, the antibacterial activity of Saturejahortensis essential oil against multi-drug resistant bacteria isolated from the urinary tract infections was investigated. During the years 2011 to 2012 a total of 36 strains of pathogenic bacteria including 12 Klebsiellapneumoniae, 12 Escherichia coli and 12 Staphylococcus aureus species were isolated from urine samples of hospitalized patients (Amir Al-Momenin Hospital, Zabol, South-eastern Iran) suffering from urinary tract infections. After bacteriological confirmatory tests, the minimum inhibitory concentrations of the essential oil of Saturejahortensis were determined using micro-dilution method. The antibiotic resistance profile of the E. coli isolates were as follows: ceftazidime (50%) cefixime (41.6%), tetracycline (75%), erythromycin (58.3%). However K. pneumoniae isolates showed resistance to ceftazidime (33.3%), cefixime (58.3%), erythromycin (75%) and S. aureus isolates were resistant to cefixime (33.3%), trimethoprim-sulfamethoxazole (41.66%), penicillin (50%), oxacillin (83.3%), ceftazidime(66.6%) and vancomycin (8.3%). The essential oil of this plant had inhibitory effect against most isolates. More than 1/3 of the E. coli isolates showed the lowest MIC (10 ppm) whereas more than 1/3 of the K. pneumoniae isolates showed the highest (250 ppm) MIC values. In contrast, equal number of S. aureus isolates showed the low MIC values (10 and 50 ppm), while the heighest MIC (250 ppm) was seen in 1/3 of isolates and moderate MIC (100 ppm) was seen in one isolate only. The Saturejahortensis essential oil has a potent antimicrobial activity against multi-drug resistant bacteria. The present study confirms the usefullness of this essential oil as antibacterial agent but further research is required to evaluate the practical value of this plant before proving its therapeutic applications.