جستجوی مقالات مرتبط با کلیدواژه « حداقل غلظت مهاری » در نشریات گروه « پزشکی »

Nowadays occurrence of resistant to clarithromycin which is a key component of eradication therapy for Helicobacter pylori strains is a worldwide health concern. Point mutations in 23srRNA gene is one of the main causes of clarithromycin resistance. This study aimed to examine rate of clarithromycin resistance and its link with 23srRNA gene point mutation.

This study was conducted on 100 patients suffering from gastric complications had referred to tehran valiasr clinic during january of 2022. Two separate biopsy samples were collected from each patient and used for pathological and microbiological examinations. Antimicrobial susceptibility tests were performed by agar dilution and PCR.

53% (53/100) of the study patients were diagnosed as H. pylori+. Pathological findings indicated that 54.7% (29/53) of the H.pylori+ patients suffered from Chronic Gastritis, 37.7% (20/53) from Sever Active Gastritis and 7.5% (4/53) with Intestinal Metaplasia. Clarithromycin resistant were found among 13.2% (7/53) of patients. The MIC values of 0.125 mg/L and 2 mg/L were determined as the MIC50 and MIC90 values, respectively. Based on PCR results, all clarithromycin resistant strains had point mutations A2142G in 23SrRNA gene.

The findings revealed the existence of point mutations in 23srRNA gene which may be related with resistance to clarithromycin in H. pylori strainsKeywords: Helicobacter pylori, Clarithromycin Resistance, Histopathological Changes, Minimum Inhibitory Concentration

Emergence of resistance to antimicrobial medications has led to the use of medicinal herbs for the treatment of infections. In this regard, this study aimed to investigate the antimicrobial effects of three extracts (i.e., ethanol/methanol, water, and acetone) of Melissa officinalis and Impatiens walleriana on four species of bacteria.

The selected bacteria, including Staphylococcus aureus, Escherichia coli, Bacillus subtilis, and Enterococcus were first activated in the culture medium of broth neutrinos. Subsequently, a suspension equivalent to half McFarland was prepared from the activated bacteria. Antimicrobial activities of the extracts were evaluated by microdilution broth and disc diffusion methods to determine the minimum inhibitory and bactericidal concentration values.

Based on the results, the Impatiens walleriana acetone extract had the most antimicrobial effects on all four species of bacteria. Moreover, acetone and ethanol/methanol extracts of Impatiens walleriana had more antimicrobial effects on E. coli than ethanol/methanol and water extracts of Melissa officinalis. In case of S. aureus, the water and ethanol/methanol extracts of both plants had almost the same minimum bactericidal and inhibitory concentration values. Finally, it can be said that all three Melissa officinalis extracts had better antimicrobial effects on Enterococcus and B. subtilis than the three Impatiens walleriana extracts.

Among all extracts, acetone extract of Impatiens walleriana showed the highest antibacterial property. Given the results and the increasing resistance of bacteria to antibiotics, it is suggested to use antibacterial compounds of plants for the treatment of infectious diseases; nevertheless, further studies should be carried out in this regard.

 Pseudomonas aeruginosa infections are resistant to antimicrobial agents and produce toxic virulence factors such as exotoxin A. Studies have shown that some nanoparticle compounds and antibiotics have a synergistic effect. Therefore, the aim of this study was to investigate the synergistic effect of silver nanoparticles and erythromycin on antibiotic-resistant P. aeruginosa.

 In this descriptive cross-sectional study, 40 cultured samples of burn wound secretions were taken from Imam Musa Kazem (PBUH) Burns Hospital in Isfahan, Iran. Diagnostic and differential tests were performed. Antibiogram was performed to obtain the bacterial resistance pattern and the exotoxin A gene was detected by PCR. The bacterial minimum inhibitory concentration (MIC) was then applied to the silver nanoparticles (shape and mean size) and erythromycin separately and a common mixture of both in 10 dilutions to investigate the synergistic effect.

   A number of 26 bacteria were strains of P. aeruginosa. Of samples, 25 (96.15%) had exotoxin A gene. All samples were sensitive to all erythromycin concentrations. The mean MIC of nanoparticles against bacteria was reported to be 2 μg/mL. A solution of 40 μg/mL erythromycin and 2 μg/mL nanoparticles was also considered as MIC solution. Pseudomonas aeruginosa is sensitive to erythromycin to very low concentrations of silver particles. But no synergistic effect between silver nanoparticles and erythromycin was reported for this bacterium. Based on PCR results and antibiotic resistance pattern, a significant number of the samples contained the exotoxin A gene and the use of erythromycin alone was not appropriate for treatment.

Campylobacter species are among foodborne pathogens that are known as the main cause of inflammatory diarrhea in humans. In this cross-sectional study, we investigated the prevalence of Campylobacter spp. and their drug resistance status in fecal samples of patients with community-acquired gastroenteritis in Tehran.

In this survey, infection with Campylobacter spp. was evaluated in 400 stool samples of patients with diarrhea. Accordingly, microscopic examination to show the presence of exudative diarrhea, rejection of fungi and parasitic infections, enrichment and culture in a specific medium under microaerophilic conditions, determination of biochemical identity, and molecular confirmation at genus and species levels for C. jejuni, C. coli, C. lari, and C. upsaliensis were performed. Antibiotic resistance patterns were determined by E-test and disk diffusion methods, and the presence of the dominant gyrA gene mutations in the quinolone-resistance domain of C. jejuni isolates was determined by using Mismatch Amplification Mutation Assay-polymerase chain reaction (MAMA-PCR)[1].

A total of 28 strains of Campylobacter were isolated from the samples obtained from the patients with diarrhea. The most common species were C. jejuni (6%), C. coli (0.5%), C. lari (0.25%), and other unknown species (0.25%). The highest antibiotic resistance rate was observed against tetracycline and ampicillin (53.5% and 50%, respectively), and the lowest rate was detected for nalidixic acid and ciprofloxacin (28.5% and 28.5%). Multiple drug resistance (MDR) phenotype was detected among 51.8% of the strains.

Results of this study indicated C. jejuni as the main Campylobacter species responsible for community-acquired diarrhea among the studied patients. The high rate of resistance to antibiotics and MDR phenotype in these strains compared with other countries is considered a risk, especially in the treatment of invasive infections.

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. 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). 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). Thyme essential oil in concentration less than its MIC in combination with ciprofloxacin via synergistic interaction reduces antibiotic MIC and antibiotic resistance.

Incidence of drug resistance against chemical antimicrobial drugs has led the use of medicinal plants for treatment of infections in recent years. The aim of this study was to examine possible antibacterial and antifungal effects of Methanolic, Ethanolic and Aqueous extracts of Ocimum basilicum plant in vitro. After preparing the extracts with maceration method, antimicrobial activities and Minimum inhibitory concentration were examined by Disk-Diffusion, serial dilution method against bacteria Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and fungi Aspergillus niger and Candida albicans. To standardize of study, we used anti biogram disks and ATCC bacteria. The results showed that, the methanolic extract of Ocimum basilicum had maximum antimicrobial activity against Staphylococcus aureus and Aspergillus niger with the diameter of inhibition zone (20±1.02 and 18±1.20mm) respectively. In addition, the minimum inhibitory concentration of Methanolic extract against Staphylococcus aureus and Aspergillus niger was documented in 12.50 and 25 mg/mL, respectively. The aqueous extract of the Ocimum basilicum did not have a good effect compared to methanolic and ethanolic extracts. Discussion & conclusions: The Ocimum basilicum methanolic extract has significant inhibitory role in the growth of pathogenic bacteria in vitro. Meanwhile, more researches are recommended due to reaching more inclusive results.

AmpC-type beta-lactamases have been implicated in group C of Amber, which includes EBC, CIT, MOX, FOX, DHA, and ACC. The active presence of these plasmid genes in clinical isolates of P.aeruginosa has resulted in resistance to a wide range of antibiotics. Therefore, we aimed to determine the minimum inhibitory concentrations (MIC) of different antibiotic groups in clinical isolates of P. aeruginosa carrying AmpC enzyme and study their relationship pattern.
In this descriptive study, the MIC of 95 P. aeruginosa isolates was determined using E-test for cefocytosine, cefpodoxime, cefotaxime, ceftazidime, ciprofloxacin, colicitin, aztreonam, and ceftriaxone antibiotics (Liofilchem, Italy). Multiplex polymerase chain reaction was used to amplify and identify plasmid genes. The Chi-squared test was used to determine the relationship between variables.
Of the 95 P. aeruginosa isolates, 95 (100%) isolates were resistant to cefoxitin, 79 (83.5%) isolates to cefpodoxime, 2 (2.1%) isolates to ceftazidime, 87 (81.57%) isolates to ceftriaxone, and 22 (23.15%) isolates were resistant to aterranum, but none of the isolates was resistant to colistin. In addition, 21 (22.1%) isolates had FOX gene, 13 (11.57%) isolates had AAC gene, 7 (36.6%) isolates had MOX gene, 4 (21.4%) isolates had CIT gene, 2 (2.1%) isolates had DHA gene, and 1 (1.05%) isolate had EBC gene. It is worth mentioning that there was a significant relationship between the presence of plasmid genes and antibiotic resistance (level of significance: P≤0.05).
The presence of the genes encoding the AmpC enzyme can provide the ground for resistance to a broad range of antibiotics.

Tooth decay has high prevalence in the world. The use of plant material for the prevention and treatment of this disease for various reasons is considered, due to the increasing resistance of bacteria to antibiotics, the high cost and adverse effects of some chemicals used in dentistry. This study was aimed to determine the antimicrobial effect of alcoholic extract of Pepper (Capsicum annuum) and eggplant skin and cap on the cariogenic streptococci.
In this study, the antimicrobial activity of ethanol extract of Capsicum annuum and eggplant skin and cap on the cariogenic streptococci, including Streptococcus mutans, Streptococcus sobrinus, and Streptococcus sanguis by microtitre plate method for MIC (Minimum Inhibitor Concentration) was performed. Data were analyzed by one-way analysis of variance using Prism 5 Graph Pad software.
MIC for the Capsicum annuum and eggplant skin for Streptococcus mutans was 250 mg/ml (SD=0.052), and for the Streptococcus sobrinus and Streptococcus sanguis was 125 mg/ml (SD=0.027). The MIC for the cap eggplant for Streptococcus mutans and Streptococcus sobrinus was 500 mg/ml (SD=0) and for S. sanguis was getting 125 mg/ml (SD=0.159).
This study showed that the herbal extracts of Capsicum annuum and eggplant skin and cap had beneficially antimicrobial effects on all three strains of cariogenic streptococci.

Background and The medlar (Mespilus germanica L., Rosaceae) is an edible fruit and modern medicine has recognized its healing properties in treatment of some diseases. There is no scientific data in literature about its activity against some bacteria. In this study, antibacterial activity of hydro-acetonic extract of medlar¢s leaf was evaluated against some bacteria.
In this experimental study, the leaves were collected from Sari, Iran. Materials were dried at room temperature and coarsely ground before extraction. The extraction was performed at room temperature by maceration method using acetone (70%) as solvent. Total phenols and tannins were determined by Folin-ciocalteu method and antibacterial effects were studied. Minimal Inhibitory Concentration (MIC) and Minimal Bactricidal Concentration (MBC) were calculated by Broth Dilution Test.
The yield of extraction was 20%. Total phenolic and tannins contents were 90±10 GAE (based on standard curve) and 10±4 /g extract, respectively. The extract showed best inhibitory and bactericidal activities against Klebsiella pneumoniae (MIC= 3.333 ± 0.0233 and MBC= 5.833 ± 0.065). The lowest MIC was observed against Vibrio Cholera (6.667±0.048) and the lowest MBC was seen against E. coli and Shigella dysentiea (9.167±0.042).
M. germanica leaf extract showed good antibacterial activities. So, this plant is potentially effective in controlling dysentery.

Fungal Oral diseases affect the majority of the population and can affect a person’s overall health. It is reported that chamomile extract contain phytomedicine capabale of suppressing oral pathogens associated with fungal diseases. The aim of this study is the assessement of chamomile extract antifungal activity on Candida albicans.
The reference strain of C. A ATCC 10231 used for this study. The70% ethanol extract of chamomile was and then made in 2-512 mg/ml concentrations. The antifungal activity of the extract was examined by determining Minimum Inhibitory Concentration (MIC) and Minimam Fungicidal Concentration (MFC) using the macro broth dilution technique and agar well diffusion method.
Results showed that the ethanol extract of Chamomile had inhibitory and fungicidal effect only in concentration of 512 mg/ml.
Comparison of the results of ethanol control group and test group showed that inhibitory and fungicidal effect of hydroalcoholic extract of chamomile is due to 70% Ethanol but not the chamomile and Ethanol extracts of chamomile has no antifungal effect on Candida albicans.

The protein lactoferrin (LF) reduces the MIC of Antibiotic vancomycin for vancomycin-resistant enterococci isolates The purpose of this research was to investigate the effect of LF on the MIC of vancomycin for vanA and VanB resistant isolates of enterococci. In this experimental study, after isolating and identifying 265 strains of enterococci from clinical specimens, The MIC test by using E-test method was performed for the vancomycin resistance enterococci specimens with the vancomycin and teicoplanin antibiotics. Using, Real time PCR method to study the presence of vanA and vanB genes in vancomycin-resistant Enterococcus. Then the effect of lactoferrin on the MIC of VRE isolates was assessed and Using SPSS software version 20 (version 20, SPSS Inc., Chicago, IL) and linear regression and Pearson correlation test with significance level P-value <0.05 was analyzed. VanA isolate at (2048µg/ml) concentration of LF showed 85 and 80 fold reduced the MIC of vancomycin in modified Etest and Microtiter methods respectively and in vanB isolate at the concentration of (512µg/ml) of LF 10 and 10.3 fold reduced the MIC of vancomycin in modified Etest and broth Microtiter methods respectively. lactoferrin index showed a significant positive correlation with reduced vancomycin MIC (P<0.001 and r= 0.183). Different concentrations of Lactoferrin protein induced reduction in VRE isolates contained van A and van B genes in vivo concentrations suggest a potential use for this protein as an adjunctive agent to vancomycin.

Pseudomonas aeruginosa is the most common cause of nosocomial infections، that known as one of the most resistant bacteria against antibiotics and show resistance to a lot of common treatment. On the same basis، the aim of the present study is evaluation of the antibacterial activity of aqueous extracts of four kinds of Iranian native plants on the growth of P. aeroginosa and compare them with antibiotics. Aqueous extracts of herbs were prepared by the soxhlet extractor and after preparing dilution، antimicrobial effect of them was determined by well diffusion and Broth dilution method on 3 different concentration Results & In this study، the highest anti-bacterial effect have been relative to Hippophae rhamnoides (17. 6 mm). The minimum inhibitory concentration of Zataria multiflora Boiss، Juglans regia L and Origanum vulgare was 25% and was recorded 12. 5% for Hippophae rhamnoides. At this research، difined all of the herbal extracts have antibacterial effect on the studied strain and this activity due to the culture، origin، growing season and effective material in plants could be different.

Infectious diseases are one of the most important agents of mortality in the world. Due to resistant of some human infectious bacteria to antibiotics, use of plant pharmaceutical herbs to control of these agents is increasing. The aim of this research was to investigate the antibacterial effect of aqueous extract of Yarrow and Salvia against ten bacterial strains of human pathogenic bacteria. Aqueous extract from Achillea millefolium and Teucrium polium species were prepared using maceration method and then were concentrated and dried using rotary apparatus.. Ten standard bacterial strains were cultured on Nutrient Broth. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of plant extract of both extract on bacteria were determined using micro dilution method at four different concentrations (0/62-1/25-2/5-5-10mg/ml). The results showed that aqueous extract from Achillea millefolium and Teucrium polium species have an inhibition effect on all tested bacteria. Staphylococcus aureus and S. saprophyticus showed the highest and lowest sensitivity to water extract of yarrow respectively. Pseudomonas aeroginosa sereus strain showed high degree of sensitivity whereas S. aureuss and Bacillus aeroginosa strains were less sensitive to extract of salvia. According to obtained results in this work and other researches in this domain, the Aqueous extracts of Yarraw and Salvia could be introduced as a biocontrol agent against pathogenic micro-organisms. Nevertheless to use each extract of plant for clinical application, chemical analysis of extracts and clinical researches are necessary.

Several studies have been done that showed honey has been therapeutic effects on infection disease like Pseudomonas infections. Our aim of this study is evaluation of the antibacterial activity of mono floral and multi floral honeys from different origin of Iran on growth of Pseudomonas aeruginosa and compare their activities with artificial honey and antibiotics. Antimicrobial effect of honey was determined by disc diffusion and broth dilution method on 5 different concentration of honey. The highest inhibition zone (16 ± 1/52 mm) was recorded from persimmon honey in disc diffusion method. In this study، the minimum inhibitory concentration (MIC) for manna honey and other natural honeys obtained 25% and 12. 5% respectively. While P. aeruginosa was inhibited at concentration of 50% (ml/ml) of artificial honey. This study showed that honey has a significant antibacterial effect on P. aeruginosa. There is a direct link between the concentration of honey and inhibition zone.

Today, research in the field of antimicrobial peptides is active. Thus, the aim of this study is to purify and determine biochemical properties (especially antimicrobial effect) of new antimicrobial peptides from skin secretions of bufo kavirensis. This is a descriptive study. The skin secretions of bufo was purified by biochemical manners and antimicrobial effects was characterized by radial dffusion assay and minimal inhibitory concentration. The sequence of peptides was also determined by using MS/MS. A novel antimicrobial peptide was obtained from skin secretions. This peptide is composed of 20 amino acids. This peptide does not present any similarity with the other antimicrobial peptides from the amphibians. Thus, it was named Maximin Bk. The peptide was subjected to antimicrobial activity assays. The Buforin–Kpeptide showed considerable antimicrobial activity against Gram positive and Gram negative bacteria (minimum inhibitory concentrations (MIC), 8.1 to 20.78 µg/ml) as well as fungi (MIC, 25.7 to 35.6 mg/ml). Moreover, this peptide showed higher antimicrobial activity against Gram-negative than against Gram-positive bacteria and fungi. Maximin Bk showed virtually low hemolytic activity, which, at a concentration of 100 μg/mL, induced 5% hemolysis. Thus, a very slight haemolytic activity was obtained against human erythrocytes. On the basis of the biological effects, Buforin–Kcan can be regarded as the potent agent for treatment of various microbial diseases.

Background and Ëvaluation of medicinal plants has shown potential antimicrobial effects which introduced many drugs with antibiotic properties. Âs there were controversies about antimicrobial action in the literature، this study evaluates the antibacterial effect of ethanolic (80%) extract of the seeds of Foeniculum vulgare plant. The disc diffusion method and determination of minimum inhibitory concentration (MÏÇ) of the extract against Staphylococcus aureus PTÇÇ 1112، Bacillus subtilis PTÇÇ 1023، Ëscherichia coli PTÇÇ 1330، and Salmunella typhi PTÇÇ 1639 were employed and Gentamycin and Âmikacin were used as standards. The hydroalcoholic extract of the seeds of Foeniculum vulgare showed concentration-dependent antibacterial activity against all tested bacteria. The hydroalcoholic extract was more effective against Ë. coli and less effective on B. subtilis. The MÏÇs were 3. 2 mg/ml and 12. 8 mg/ml for quoted bacteria respectively. Çonclusion: The results concluded that the ethanolic extract of Foeniculum vulgare is a potential natural antibacterial agent، however its effect is dependent on the source and extraction method.

Medical plants entail numerous therapeutic capabilities due to their antimicrobial activities. During the present study, the antimicrobial activity of aqueous and methanol extracts of Heracoleum Persicum was determined in vitro. We have gathered the aforementioned plant from heights of Ashkour near Tonkabon. The antimicrobial activity of aqueous and methanol extracts was determined against 14 bacterial and 2 fungal specimens according to the disc diffusion, MIC (minimal inhibitory concentration), and MBC (maximum bactericidal concentration). The aqueous extract of Heracoleum Persicum failed to show antimicrobial activity, however, the methanol extract was effective against bacillus, streptococcous, enterococcous and nocardia. The methanol extract of Heracoleum Persicum has antibacterial activity. Further studies are strongly recommended to find out the possible therapeutic capability of this plant in infectious diseases.