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Background and Objective: Klebsiella species are gram-negative bacteria with positive voges proskauer (VP) reaction. Klebsiella species are found as commensal in human digestive and respiratory system. This group of organisms can create a serious health hazards in hospitalized patients, and their ability to drug resistance is a major health problems. This study was done to evaluate the efficacy of Ciprofloxacin, Ceftizoxims and Carbenicillin on Klebsiella species isolated from hospital specimens. Materials and Methods: In this laboratory study, 1200 clinical samples were isolated from patients in Imam Khomeini hospital, Tehran, Iran. The identification Klebsiella species were carried out according to conventional biochemical tests. The minimum inhibitory concentration (MIC) of carbenicillin, ceftizoxime, and ciprofloxacin antibiotics were determined using Macrodilution broth test. Results: Out of 1200 isolated samples, 25% were identified as Klebsiella species. 73% of identified Klebsiella were obtained from urine samples. Klebsiella.peumoniae with rate of 94% was the most abundant among other species. The results of MIC and minimum bactericidal concentration by using standard microdilution method showed drug resistance range of 16-1024 μg/ml, 4-256 μg/ml and 0.25-16 μg/ml for carbenicillin, ceftizoxime, and ciprofloxacin, respectivley. In general, 94%, 6% and 1% of species were resistance to carbenicillin, ceftizoxime and ciprofloxacin, respectively. Conclusion: Ciprofloxacin and Ceftizoxime are suitable for the treatment of infections due to Klebsiella species.

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Background and Objective: Ferula gummosa Boiss. (Barije.) contain medical and antimicrobial properties. This study was done to determine the effect of aqueous and alcoholic extracts of roots of Ferula gummosa Boiss. on the growth of Pseudomonas aeruginosa. Materials and Methods: In this laboratory study, the plant was dried in dark place and aqueous, alcoholic extracts of Barije's root, powder were prepared using Soxhlet method. The efficacy of 0.1 dilution of different values of extracts of Ferula gummosa Boiss. on the strain of Pseudomonas aeruginosa (PTCC 1430) were evaluated by disk diffusion, Agar-well diffusion, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) methods. Results: Pseudomonas aeruginosa was completely resistant to the aqueous extract, and the MIC for the methanol and ethanol extracts was 1.25×10⁴ μg/ml and 6.25×10³ μg/ml, respectively. Conclusion: Methanolic and ethanolic extracts of Ferula gummosa Boiss. have antimicrobial activity against Pseudomonas aeruginosa in in-vitro model.

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Background and Objective: Ciprofloxacin is effective against a wide range of bacteria, particularly Enterobacteriaceae. However, studies have shown that the resistance of Escherichia coli to ciprofloxacin is enhanced. Thyme is one of the medicinal plants whose essential oil has anti-microbial effects. This study was aimed to investigate the antimicrobial properties of local Thyme essential oil alone and in combination with ciprofloxacin on Escherichia coli mutant strain with intermediate resistance.
Methods: In this descriptive laboratory study, Thyme plants (10 samples) were collected from Lorestan Province, west of Iran during 2016. Theses samples belonged to T. eriocali species. Plant essential oil was extracted by distillation method with Clevenger equipment. The antimicrobial properties of local thyme were determined by measuring minimum inhibitory concentration (MIC) of it alone and in combination with ciprofloxacin using sequential dilution method (macrodilution and microdilution methods) in Escherichia coli strains. Minimum bactericidal concentration (MBC) was measured by cultivation method. The interaction between essential oil and ciprofloxacin was determined by calculation of fractional inhibitory concentration index (FICI).
Results: MIC of essential oil for wild type strain MG1655 and mutant strain RE6 was 8 and 10 µl/ml, respectively. MBC was equal to MIC. 0.4 µl/ml of essential oil decreased 45 fold the MIC of ciprofloxacin in mutant strain and produced synergistic interaction (FICI=0.06).
Conclusion: Thyme essential oil in concentration less than its MIC in combination with ciprofloxacin via synergistic interaction reduces antibiotic MIC and antibiotic resistance.