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Showing 3 results for Minimum Inhibitory Concentration.
Study of Antimicrobial Effects of Trigonella Foenum hydro-alcoholic Extract on Different Bacterial Strains
R Abiri, Mb Majnooni, P Malek Khattabi, H Adibi,
Volume 3, Issue 1 (4-2009)
Abstract
Abstract Background and objectives: Infectious diseases are the leading cause of mortality in the world. With the increase of Microbial resistance to chemical antibiotics and low side effects of medicinal herbs, it has become of great importance to use herbs as a source of antimicrobial compounds. Material and Methods: In this study, the extract of Trigonella foenum leaf and seed was prepared using 70% ethanol. Minimum Inhibitory Concentrations (MIC) and antimicrobial Sensitivity were determined using microdilution broth and disk diffusion method, respectively. The Results were compared with Gentamicin, Ciprofloxacin and Fluconasole. The tested strains were: clinical strains of Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia, Enterococcus faecium, Candida albicans and two standard strains of Staphylococcus aureus and Pseudomonas aeruginosa. Results: The least MIC of the leaf extract against the standard strain of S. S. aureus, E. faecium and clinical S. aureus is 64 μg/ml and for seed extract against E. faecium and Standard S. S. aureus is also 64 μg/ml. The largest diameter of inhibitory zone caused by leaf extract on Standard S. S. aureus is 23mm, and for seed against E. faecium is 18 mm. Conclusion: Because of antimicrobial effects of leaf and seed extract of Trigonella foenum, these extracts can be used as anti microbial compounds in pharmaceutical and food industries. Therefore, the isolation, identification and purification of the antimicrobial compounds of the extracts are recommended. Key words: Trigonella foenum, Antimicrobial effects, Minimum inhibitory concentration.
Comparison of Disk Diffusion and E-Test with the Reference Method of Microbroth Dilution for Susceptibility Testing of Acinetobacter baumannii Isolates to Tetracyclines
Abdollah Ardebili , Malihe Talebi , Abdolaziz Rastegar Lari ,
Volume 10, Issue 1 (1-2016)
Abstract

Abstract

      Background and Objective: Due to the continuous increase of multidrug-resistant Acinetobacter baumannii strains around the world, decision making for an effective treatment of infections caused by this organism depends on the results of antimicrobial susceptibility tests. In this study, the validity of disk diffusion and E-test methods was assessed by their comparison with the reference method of microbroth dilution for three antibiotics of tetracycline, doxycycline and minocycline.

     Methods: Total of 68 A. baumannii isolates were obtained from patients hospitalized in the burn center of Shahid Motahari Hospital in Tehran, Iran. Susceptibility of the Acinetobacter isolates was evaluated using the disk diffusion, E-test and microbroth dilution methods, according to the guidelines of Clinical and Laboratory Standards Institute.

     Results: Among the isolates, 82.3% were tetracycline-resistant (with minimum inhibitory concentration 50 (MIC50) and MIC90 of 32 and more than 32 µg/ml, respectively and 41.2% were doxycycline-resistant (with MIC50 and MIC90 of 4 and more than 32 µg/ml, respectively). Minocycline, with resistance of up to 13.3% (MIC50 and MIC90 of 1 and 8 µg/ml, respectively) showed the highest antimicrobial activity against the A. baumannii isolates. Antimicrobial susceptibility of bacteria was different depending on the type of methods used. No very major error was observed in any of the methods of susceptibility testing. Overall, the level of major and minor errors in the E-test was lower than the disk diffusion method.

     Conclusion: The results of this study indicate that minocycline has notably high antimicrobial activity against A. baumannii compared to other antibiotics of the tetracycline group.


Biosynthesis of Silver Nanoparticles Using Bacteria Isolates from Wastewater
Shima Kazemi , Monir Doudi , Gholm Reza Amiri ,
Volume 11, Issue 6 (11-2017)
Abstract
ABSTRACT
           Background and Objectives: Development of ecofriendly processes for the synthesis of metal nanoparticles is of great importance in the field of nanotechnology. Microorganisms such as bacteria could be suitable candidates for bioproduction of nanoparticles due to their simplicity and high compatibility with the environment. The aim of this study was to use bacteria isolates from the effluent of wastewater treatment plants to produce silver nanoparticles.
         Methods: For identifying silver-resistant microorganisms, we used the agar diffusion method using PHG II medium containing 0.5 mM silver to determine minimum inhibitory concentration. Bacterial identification was done with biochemical testing and polymerase chain reaction (colony PCR). Finally, silver nanoparticles were produced in the desired bacteria, and the properties of these nanoparticles were studied.
         Results: We found five silver-resistant bacteria among which Stenotrophomonas maltophilia strain MS8 showed the highest resistance (MIC= 6 mM). The bacterium was able to synthesize silver nanoparticles in spherical shapes. The results obtained from visual observations using UV-VIS, TEM and XRD showed that the bacterium was able to reduce silver ions into silver nanoparticles with maximum size of 20 nm.
Conclusion: Based on our findings, this bacterium could be useful for biosynthesis of silver nanoparticles.
          KEYWORDS: Bacteria, Biosynthesis, Minimum Inhibitory Concentration. 

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