جستجوی مقالات مرتبط با کلیدواژه « disk diffusion » در نشریات گروه « پزشکی »

Vaginal candidiasis is a common cause of vaginal infections. Currently, for treatment of these infections, fluconazole is prescribed more than other drugs; so determining the drug resistance of Candida to fluconazole and comparing it with itraconazole as a substitute has been one of the main objectives of this study.

Of 180 patients with symptoms of vaginal candidiasis, clinical examination, sampling and culture were performed. Candida albicans were identified by morphological and physiological methods and non-Candida albicans candida isolates by PCR-RFLP method. Susceptibility testing for antifungal drugs was performed by disk diffusion method based on CLSI M44-A protocol.

Out of 180 patients, 93 patients with positive culture and 98 strain of Candida were isolated. The mean age of patients was 30±0.73 years and the most common clinical complaints was itching (>98%) and vaginal discharge (88%). Candida albicans (80.61%) was the most common causative agent. The resistance of Candida albicans to fluconazole and itraconazole was 45.6% and 16.5%, respectively, and for non-albicans candida isolates were 53% and 42%, respectively. This difference was statistically significant (P<0.0001).

The results of this study suggest that culturing of vaginal samples have essential role for diagnosis of vaginal candidiasis, and treatment with antifungal drugs should be performed after antifungal susceptibility tests.

The emergence of antibiotic resistance has been considered on efforts to achieve new drug combinations. Antimicrobial compounds derived from plants, eliminated bacteria with different mechanisms of antibiotics. The aim of this study was to evaluate the Antimicrobial effects of methanolic and acetone extracts of Peganum harmala and Lavandula angustifolia against some of human pathogenic microorganism.

The microorganisms used in this study were prepared from Persian Type Culture Collection, Iran. Soxhlet extraction method was used for extraction. Disk diffusion method was used to study the effect of antimicrobial and broth microdilution method were used to determine the minimum inhibitory concentration (MIC) and Minimum Bactericidal Concentration (MBC).

The results showed that methanolic extract of both P.harmala and L.angustifolia have antibacterial effect, while between acetone extract only acetone extract of P.harmala was antibacterial activity. The most antibacterial effect was related to methanolic extract of P.harmala, so that, inhibition zone diameter affected of this extract againts S. aureus was 19/67 Millimeters. The results showed that both methanolic extract have antifungal activity. Minimum bactericidal concentration for bacteria and fungi was 1000 mg/ml.

According to the study it was found that methanolic extract of both P.harmala and L.angustifolia possesses significant antibacterial and antifungal activity against pathogenic bacteria and C. albicans, Therefore, this extract can be considered as a natural herbal product for controlling bacterial and fungal infections.

The accumulation of airborne bioaerosols on filtration media and their gradual proliferation in the presence of appropriate moisture and environmental conditions is one of the major problems against using these media.The use of hybrid media containing antibacterial agents is one of the available solutions to this problem. The present study was aimed to fabricate nonwoven nanofiber media with antibacterial activity using electrospinning process.

Polyurethane-chitosan nanofiber media with weight ratios of 100 to 0, 90 to 10, 80 to 20, and 70 to 30 were fabricated by simultaneous electrospinning process. After preparation of the nanofiber media, their antibacterial properties were evaluated by standard methods of disk diffusion (ISO 20645) and colony counting (ISO 20743).

The bacterial growth inhibition zones gradually are formed around the examined samples by adding the layers of chitosan nanofibers to the polyurethane media indicating the antibacterial activity of these substrates. The evaluation of antibacterial activity of samples by both methods showed that the media with polyurethane to chitosan weight ratio of 70 to 30 had suitable antibacterial activity. The mean value of bacterial growth inhibition zone and antibacterial activity for polyurethane-chitosan (70/30) media were 0.226 mm and 2.222, respectively.

Evaluating the antibacterial activity of prepared nanofiber media indicated that antibacterial nanofiber media can be created by adding chitosan nanofibers as antimicrobial agents to the polyurethane nanofiber.

The increased resistance of microorganisms to common antibiotics is one of the major therapeutic challenges for patients. The present study aimed to compare the antibiogram results of two types of antibiotic discs and validate them by the Epsilometer test (E-test) method on bacteria with high antibiotic resistance patterns.

This descriptive-analytical study was performed by the census method on 176 patients admitted to different wards of Sina Hospital in Hamadan from March 2016 to March 2019. The patients entered the study with a positive culture result and underwent the antibiogram using two types of discs. Following that, validation was performed by the E-test method in cases with significant differences. Finally, the results were described and analyzed in SPSS software (version 16) at a 95% confidence interval.

Out of 176 patients, 80 (45.4%) and 96 (54.5%) cases were male and female, respectively. The mean age of patients was reported as 62.44.±20.47 years. The most common culture sites were trachea (45.5%) and urine (42.6%), and the most common cultured microorganisms were E.coli (33.5%), Klebsiella (29.5%), and Acinetobacter (18.8%). The highest correlation coefficients of the results by disk diffusion method were observed in levofloxacin (r=1.00), piperacillin (r=0.917), ciprofloxacin (r=0.907), cotrimoxazole (r=0.904). On the other hand, the lowest correlation coefficients were related to imipenem (r=0.634), cefoxitin (r=0.556), and ceftriaxone (r=0.552).

As evidenced by the obtained results, significant differences were detected between the results of antibiogram in Iranian and imported disks. After verification and validation using E.test, the percentage of agreement was in favor of imported disks.

 Shigella species are one of the most common causes of bacillary dysentery and sometimes death especially in children and immune-compromised individuals. The diversity of disease-causing species and the emergence of drug resistance make it difficult to select the appropriate antibiotic to treat shigellosis. One of the important causes of resistance in Shigella isolates is the presence of genes encoding broad-spectrum beta-lactamase enzymes. The aim of this study was to determine the frequency of Shigella sonnei strains producing CTX-M-2, CTX-M-8, and CMY beta-lactamase genes by Multiplex PCR and to investigate their association with antibiotic resistance in Shigella sonnei strains.

   This descriptive cross-sectional study was conducted in a period of 6 months from the beginning of June to the end of October 2016. A total of 200 diarrhea specimens were collected from the patients with suspected shigellosis from the Childrenchr('39')s Medical Center (Tehran). The antibiotic susceptibility testing was performed using disk diffusion method on Müller-Hinton agar in accordance with CLSI instructions. After DNA extraction, the presence of CTX-M-2, CTX-M-8, and Ampc-dependent CMY genes was determined by Multiplex-PCR using specific primers.

   From all the samples, 60 (30%) Shigella sonnei strains were obtained using standard microbiological and biochemical tests. Majority of the strains were resistant to erythromycin (26 strains, 43.3%) and cefepime (24 strains, 40%). The molecular test results showed that 40 (66.6%) and 33 (55%) of the strains carried the CTX-M-8 and CMY genes, respectively (P<0.05). The CTX-M-2 gene was not detected in any of the samples.

  The results indicate a high frequency of CMY gene among Shigella sonnei isolates and higher resistance of these strains was found against erythromycin and cefepime. Therefore, careful medical care and proper and timely use of appropriate antibiotics to prevent the spread of resistant isolates seems inevitable.

Urinary tract infections are among the most prevalent diseases in children and can lead to serious complications if improperly treated with antibiotics. This study aimed to determine the bacteriological factors and resistance of children to urinary infection antibiotics. This descriptive and cross-sectional research was performed on 160 children, who referred to Motahari Hospital in Urmia with a positive urine culture. The desired strains were recognized and identified using biochemical tests and differential culture media. In addition, antibiotic resistance pattern of the strains was determined by disc fusion method (Kirby-Bauer) as recommended by CLSI. Moreover, data analysis was performed using Chi-square, and P-value of less than 0.05 was considered significant.  Of 160 children assessed, 119 were female, and 41 were male. According to the results, the highest prevalence of urinary infection was related to the age range below two years. In addition, the most and least strains separated from urine cultures included E.coli (81.3%) and S.saprophyticus (1.9%), respectively. Furthermore, E.coli isolates had the most resistance to cotrimoxazole (64.6%), and nitrofurantoin was recognized as the most effective antibiotic with 90% sensitivity. According to the results of the study, the use of nitrofurantoin, ciprofloxacin, and gentamicin antibiotics is recommended for primary treatment of urinary infections. Given the different frequency distribution of antibiotic resistance in various regions and periods, it is suggested that antibiotic resistance be assessed periodically to control infection.

Today, the use of natural ingredients in the food industry is one of the most important discussions in biotechnology. Medlar is an herbs that its therapeutic effects has been considered from the past years. The aim of this study was to determine of the antibacterial effects of methanolic extract of medlar leaves against some of foodborne pathogenic bacteria in vitro.

In this in vitro study, the fresh leaves of the Medlar were collected from the Lalam village. Soxhlet method was used to preparation of the medlar leaf extract. Disk diffusion method was used to evaluation of the antibacterial effect and broth microdilution method were used to determine the minimum inhibitory concentration and minimum bactericidal concentration.

The maximum antibacterial activity of this extract was against Staphylococcus aureus that inhibitory zone diameter around it was 31.83 Millimeters. MIC for all tested bacteria except Pseudomonas aeruginosa was 62.5 mg/ml and MBC value of the leaves extract was variable from 62.5 to 500 mg/ml.

The results of this study show that methanolic extract of medlar leaves has a strong antibacterial effect on both gram positive and gram negative foodborne pathogenic bacteria, therefore this extract probably can be considered as a natural herbal ingredients in the form of antimicrobial or food preservative agent.

In this study, the effect of Myrtus extracts on 25 methicillin resistant Staphylococcus aureus (MRSA) and Escherichia coli ESBL strains isolated from patients were compared by two methods.

15 methicillin-resistant Staphylococcus aureus (MRSA) and 10 Escherichia coli ESBL isolates were used in this study. Fresh Leaves of Myrtus were collected from the herbal medicine farm. Extraction was performed using a reflux distillation. The effect of concentrations 0.195-100 micrograms per ml of Myrtus extract on clinical isolates was analyzed in disk diffusion method compared with micro broth dilution method and with MTT in 545 nm on an ELISA reader apparatus.
Findings: Inhibition zone diameter for the minimum effective concentration of 50 micrograms per milliliter in all isolates of ESBL and MRSA were as 8±1 mm and 11±1. Minimum Inhibitory Concentration (MIC) was 6.25mic/ml and Minimum Bactericidal Concentration (MBC) was determined 12.5mic/ml for E. coli ESBL. Furthermore, the amounts for MIC and MBC was determined as 12.5 and 25 mic/ml, respectively for Staphylococcus aureus.

The results of this study showed compliance of two methods in evaluation of drug-resistant clinical isolates. It was proved that the disk diffusion method could be determining range of effective concentration but micro broth method determines the effective concentration carefully. It is recommended that results obtained from disk diffusion not to be basis for final decisions in traditional medicine studies. Bacterial behavior in the broth and determination of the point of death greatly increases the accuracy of the results.

Introducrtion: Fluoroquinolones are among useful antibiotics against infections caused by Staphylococcus aureus, but today resistance to these classes of antibiotics is a serious problem in patient’s treatments. Overexpression of norA gene is a Fluoroquinolone resistance mechanism in Staphylococcus aureus to be studied through our investigation.
In this study, 50 Staphylococcus aureus strains were isolated from nasal infection in Sanandaj town. These strains were then identified by conventional biochemical tests. Disk diffusion testing for antibiotic resistance assessment and PCR for existence of norA gene were done. Then, PCR products were sent to Bioneer Company for sequential testing. As a result, nucleotides and amino acid mutations were studied, based on sequencing results and Expasy translator.
Findings: The results of biochemical tests were as coagulase, mannitol fermentation, DNase and hemolysis positive, novobiocin sensitive and polymyxin resistance. Oxacillin (42%), erythromycin (46%), doxycyclin (10%), amikacin (20%), tetracycline (24%), penicillin (68%), ciprofloxacin (10%), vancomycin (6%), nalidixic acid (70%) were the antibiotics to which resistance rate was assessed. All the resistance strains had norA gene and 4 identical points of mutation were identified as, G491->A, C537-> T, C593-> C and A585->G respectively. Then, after translation in D315 base, aspartic acid (D) had been converted into Glycine (G).
Discussion & According to our results, common nucleotide and amino acid mutations were observed in four strains of ciprofloxacin resistant Staphylococcus aureus. Therefore, more studies are needed to find out if the mentioned mutation is the cause of overexpression of norA

Shigella species are one of the most common causes of dysentery and sometimes death, especially in children and those with immunodeficiency. The variety of causative agents (Shigella species) and the development of drug-resistant strains make it difficult to select an appropriate antibiotic for the treatment of shigellosis. One of the most important factors involved in the resistance of Shigella isolates is the presence of extended spectrum beta lactamases (ESBLs) genes. The aim of this study was to determine the frequency of blaPER, blaGES and blaVEB genes in Shigella sonnei isolated from patients with dysentery using multiplex-PCR method and to determine the antibiotic susceptibility patterns of these isolates.
A total of 60 isolates of Shigella sonnei were collected from different hospitals and medical ýdiagnostic laboratories in Kerman province. Specimens from different age groups were cultivated in special media ýand confirmed by biochemical tests. The presence of blaPER, blaGES and blaVEB genes were ýinvestigated using specific primers and multiplex-PCR method. Antibiotic susceptibility test was ýperformed by disc diffusion method based on CLSI standards. ý
Multiplex-PCR results showed three samples had blaPER gene, but none of them had blaVEB or blaGES ýgenes. Also, the results of antibiotic susceptibility test showed the highest resistance for amoxicillin- clavulanic ýacid (53.3%) antibiotic and the highest sensitivity for tetracycline (85%) antibiotic.ý
The results of the experiments indicated the presence of blaPER gene in Shigella sonnei isolates. In ýaddition, the results showed high resistance of isolates to amoxicillin clavulanic acid and ceftriaxone ýantibiotics. Therefore, careful medical care and proper and timely use of appropriate antibiotics are essential to ýprevent the spread of resistant isolates.

Background and Medicinal plants have gained much interest in today’s world because they have fewer adverse effects compared to chemical drugs. Urtica dioica L could be used in treatment of some chronic diseases. This study aimed at investigating its treatment properties in vitro.
Different parts of the plant were collected and the extract was prepared using maceration and percolation. The antibacterial effects of the plant were identified using disk diffusion method. The MIC and MBC values were determined using dilution method against Listeria Monocytogenes (PTCC 1294), Staphylococcus aureus (ATCC 25923), Proteus vulgaris (ATCC 13315), Kellebsiella pneumoniae (PTCC 1053), and Candida albicans (ATCC 10231). The major components in the extract were identified by Gas Chromatography (GC). The extract consisted of 20 different combinations, including Neophytadiene (21.25%), Phthaleic acid (15.8%), phthalate Dibutyl (37.7%), maleate Bis (2-ethyl hexyl 32.6%), and 1,2 - Benzenedicarboxylic acid (62.7%). The amount of these compounds were higher in leaves.
The aqueous extract obtained from different organs of Urtica dioica L was found to have more antibacterial effect (the leaf and root at dilution of 5 mg /ml) compared to those of the alcoholic extract. In different dilutions, it also exhibited more antifungal effect on Candida albicans.
According to this study, Urtica dioica has antibacterial and antifungal properties, therefore, it could be used against a broad spectrum of microorganisms.

Hypercom perfuratum has medicinal properties in traditional medicine with antidepressant and anti-microbial effects. In this study, a new form of aqueous extract of Hypercom was prepared as a micro emulsion form, and its antimicrobial properties was investigated in comparison with ordinary aqueous extract on clinical strains of gram-negative bacteria.
Ten types of clinical strains were investigated in this work. Hypericum extract was prepared by water in boiling temperature and micro emulsion with the help of two types of emulsifiers. Antibacterial properties of the two materials were performed by determining the inhibition zone in a disk diffusion method and the measurement of minimum inhibitory concentrations (MIC) by the microplate dilution and a ELISA reader device.
Salmonella typhi has the highest zone of inhibition around 42 mm at a concentration of 8 mg/ml for extract and 30 mm in 0.1mg/ml micro emulsion but Pseudomonas had no zone. The MIC with microplate for Salmonella had greatest effect on the amount of 0.01563 mg/ml for Shigella concentration of 0.00625 mg/ml respectively. MIC for E. coli and Proteus extract 0.5 mg/ml and the microemulsion 0.025 mg/ml for both bacteria.
Comparison of Hypercom extract and its microemulsion form on gram negative bacteria confirmed that microemulsion in lower concentrations had the antibacterial effect equal to aqueous extract. The use of microemulsion of the extract was recommended in clinical study of herbal medicines.

With increase Staphylococcus epidermidis infections, discrimination between invasive and non-invasive S. epidermidis strains and determination of drug resistance, for diagnosis and treatment is important.
From August 2014 to March 2015, 123 strains isolated from patients and medical instruments from Ali Asghar and Hazrat Rasoul hospitals were used to discriminate invasive and contaminating S. epidermidis strains by ica, atlE, agrA, sarA, and mecA genes by Multiplex PCR method. Also, according to the CLSI standards, resistance to cefoxitin, linzeolid, clindamycin, erythromycin and tetracycline were tested by disk diffusion method and vancomycin E-test method.
prevalence of ica and mecA genes were 85% and 75% in invasive strains and 20% and 51% in contaminating strains, respectively. The resistance level to cefoxitin, tetracycline, clindamycin and erythromycin antibiotics in invasive strains were: 75℅, 35℅, 37℅, 76℅ and in contaminating strains were; 51℅, 40℅, 30℅, 64℅, respectively. Resistance to vancomycin and linezolid was not observed in this study.
This study shown that ica gene can be used as a suitable marker for discrimination between invasive and contaminating isolates. Also, vancomycin is a better choice for the treatment of resistant patients to methicillin.

Using active antimicrobial packaging reduce the risks of growth of pathogenic or spoilage microorganisms in foods. In this study, antimicrobial activity of poly lactic acid (PLA) films containing different concentrations (0, 0.5, 1 and 1.5%) of Trachyspermum ammi essential oil and ethanolic extract of propolis (0, 1 and 2%) was evaluated against Listeria monocytogenes, Staphylococcus aureus, Escherichia coli O157:H7 and vibrio parahaemolyticus by using disk diffusion assay.
Circular discs of poly lactic acid films incorporated by essential oil and ethanolic extract of propolis, prepared by casting method on glass petri dishes, were placed on Muller-Hinton agar plates that previously inoculated by tested bacteria. Diameters of inhibition zones were measured after 24 h incubation of plates at 35o C, by using Digital Caliper and Digimizer software.
Result of this study showed that the inhibition zone was increased with increasing concentration of essential oil for all tested bacteria. Also, gram positive bacteria were more sensitive to the poly lactic acid films containing essential oil than gram negative bacteria. The results revealed that L. monocytogenes was the most sensitive bacteria against films containing Trachyspermum ammi essential oil alone or in combination by ethanolic extract of propolis. Also, poly lactic acid films containing ethanolic extract of propolis showed no inhibitory effects against all tested bacteria.
Poly lactic acid films containing Trachyspermum ammi essential oil have a high potential for antimicrobial food packaging applications to enhance the safety of food products.