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Showing 4 results for Staphylococcus Aureus
Effects of sub-inhibitory concentrations of German chamomile (Matricaria recotita) extracts on the activity of catalase enzyme of S. aureus
Gholamreza Goudarzi , Moteza Satari , Saeed Amir Aslan Zadeh , Mansour Godaezi , Mohsen Bigdeli ,
Volume 7, Issue 3 (12-2005)
Abstract
Background: German chamomile (Matricaria recotita) as a medicinal plant has several therapeutic effects. Since the extract of this plant contains a high amount of α-bisabolol (Terpenoid) its antibacterial properties can be considered. Staphylococcus aureus as a pathogenic bacterium is important in clinical situations and food hygiene. So, investigation of effects of antibacterial compounds against this bacterium is important. Catalase as decomposing enzyme of hydrogen peroxide has important roles in physiology, identification and pathogenesis of many bacteria such as S. aureus. We evaluated the effect of sub-inhibitory concentrations of German chamomile alcoholic extract on the activity of S. aureus catalase. Materials and methods: German chamomile was prepared from the Agricultural Research Center of Tehran. Extraction was performed by ethanol 85°. Minimum inhibitory concentration and minimum bactericidal concentration of the extract against the standard strain of S. aureus was determined by tube dilution method in broth media. Effect of sub-inhibitory concentrations of the extract on catalase activity of the given bacteria was determined by titration method using KMnO4. Findings: The extract showed growth inhibitory effect at dilution of and at dilution of showed bactericidal effect on standard strain. Dilutions of and as sub-inhibitory concentrations, decreased catalase activity prominently. Conclusion: Significant decrease of catalase activity at sub-inhibitory concentrations of this extract shows that this extract affects the production of catalase at different levels such as transcription, translation or transport and etc. Therefore, it is necessary to further study this extract. This enzyme can be a new target for production of novel antimicrobial agents.
The antibacterial activity of Andricus Moreae gall methanol and acetone extracts of Quercus Infectoria against gram positive bacteria
Fereshte Jahaniyan-Najaf Abadi , Maryam , Mohammadi-Sichani , Majid Tavakoli,
Volume 15, Issue 2 (8-2013)
Abstract
Background: Quercus infectoria gall (Oak) has a long history of use as a medicinal plant. Andricus moreae galls arise on young branches of Quercus infectoria as a result of attack by bees.In this research, the antibacterial activity of methanol and acetone extracts of gall (Quercus infectoria) against Staphylococcus aureus, Bacillus cereus, B.subtilis strains was evaluated. Material and methods: this empirical-experimental study was carried out in Autumn,2011. Getlls were collected from Lorestan oak forests and then were dried and grinded. Acetone and methanol extracts of the galls were prepared by maceration. The viscosities of 50,25,12.5,6.25,3.12 and 1.56 mg/ml were provided from methanol and aceton extracs by serial dilution method. The agar plate well diffusion method was used for antibacterial assay of different samples. Broth microdillution method was used for evaluate MIC and MBC of extracts. Data was analyzed by SPSS-16 software. Results: All extracts demonstrated significant inhibitory effect against selected bacterial strains. There were statistically significant correlations between antibacterial activity and extracts concentration (p<0.05). Antibacterial activity of Andricus moreae gall methanol and acetone extracts against Staphylococcus aureus was more than Bacillus cereus, B.subtilis. The MIC values of the Andricus moreae gall extracts ranged from 1.56 mg/ml to 3.13 mg/ml whereas the MBC values ranged from 3.13mg/ml to 6.25 mg/ml. Conclusion: Methanol and acetone extracts of Andricus moreae were effective against all of tested bacteria. These findings show that methanol and acetone extracts of galls of Quercus infectoria may can be suggested as a natural antibacterial treatment .
Investigation of the Antibacterial Effect of Selenium Nanoparticles and Sea Cucumber Extract on Staphylococcus aureus, Klebsiella pneumoniae, and Bacillus cereus bacteria
Mahnaz Mohammadi,
Volume 24, Issue 4 (3-2023)
Abstract
Background: Many studies have been conducted in the field on the effects of industrial and chemical antibacterial substance abuse on human health and also the resistance of a wide range of bacterial species to antibiotics. Sea cucumber is one of the important aquatic animals which has therapeutic and nutritional properties. The purpose of this study is to investigate the antibacterial effect of selenium nanoparticles and sea cucumber extract on Staphylococcus aureus, Klebsiella pneumoniae, and Bacillus cereus bacteria.
Materials and Methods: The antibacterial activity of sea cucumber extract and selenium nanoparticles was investigated on three types of bacteria using the standard methods of disc diffusion, welling, determining the minimum inhibitory concentration, and determining the minimum lethal concentration. For comparing the antibacterial effects of these bacteria, the one-way ANOVA test and Scheffé test of multiple comparisons were deployed.
Results: The results of this study showed that the methanolic extract of sea cucumber with a concentration of 10 mg/ml, as well as nano-selenium with a concentration of 1 mg/ml, and the combination of a concentration of 10 mg/ml of sea cucumber extract with 1 mg/ml of selenium nanoparticles has the best antibacterial effect on the three bacteria in question.
Conclusion: The combination of sea cucumber extract and selenium nanoparticles has a higher level of antibacterial properties.                                                                                                                     

Comparative Investigation of the Antibiofilm Effect of Colloidal Solution of Silver Nanoparticles and Gentamicin on the Biofilm Formed by Staphylococcus aureus Isolates
Zahra Atefi, Nadia Kazemipour,
Volume 26, Issue 1 (4-2024)
Abstract
Background: Staphylococcus aureus is an opportunistic pathogen that plays a role in hospital infections. Due to the ability of this bacteria to produce biofilm, its antibiotic resistance has increased. Silver nanoparticles (AgNPs), due to their small size, can penetrate bacterial cells and destroy the bacterial biofilm. The present study aimed to investigate the anti-biofilm effect of AgNPs and gentamicin on clinical Staphylococcus aureus.
Materials and Methods: Staphylococcus aureus isolates were collected from health centers in Kerman, Iran, and identified by biochemical tests. The antibiotic resistance of the isolates was evaluated against antibiotics, and then, the minimum inhibitory concentration (MIC) of the isolates was assessed by gentamicin and AgNPs. Bacterial isolates were exposed to 2 MIC, 1 MIC, ½ MIC, and ¼ MIC of gentamicin and AgNPs separately, and the results were compared.
Results: The 100% resistance of isolates to oxacillin and penicillin antibiotics was observed, and the resistance percentages 63.33%, 6.66%, and 3.33% to tetracycline, ciprofloxacin and gentamicin, respectively, were confirmed. The MIC of the isolates was from 64 μg/ml to 32 μg/ml against gentamicin, and it was from 10.62 ppm to 5.31 ppm against AgNPs. Comparing the anti-biofilm effect of AgNPs and gentamicin at 1 MIC, ½ MIC, and ¼ MIC, there was a significant difference at the 5% probability level, and the anti-biofilm effect of AgNPs was better than gentamicin.
Conclusion: According to the obtained results, it is suggested that AgNPs be used to control and destroy the biofilms formed by Staphylococcus aureus with further research.

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