scholarly journals Antimicrobial Effect of Different Sizes of Nano Zinc Oxide on Oral Microorganisms

2019 ◽  
Author(s):  
Fatemeh Mirhosseini ◽  
Motahareh Amiri ◽  
Alireza Daneshkazemi ◽  
Hengameh Zandi ◽  
Zoleikha Sadat Javadi
Keyword(s):  
Particle Size ◽  
Zinc Oxide ◽  
Antimicrobial Effect ◽  
Inhibition Zone ◽  
Diffusion Method ◽  
Disk Diffusion Method ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Inhibition Zones ◽  
20 Nm

Objectives: The purpose of the present study was to evaluate the antimicrobial effect of various sizes and concentrations of zinc oxide (ZnO) nanoparticles on Streptococcus mutans (S. mutans), Enterococcus faecalis (E. faecalis), Lactobacillus fermentum (L. fermentum), and Candida albicans (C. albicans). Materials and Methods: Solutions at the concentration of 10 µg/ml were prepared using 20-nm, 40-nm, and 140-nm nano ZnO (nZnO) powder. The antimicrobial     effect of nZnO was determined using the disk diffusion method. The inhibition       zone (mm) was measured using a ruler. Data were analyzed by analysis of variance (ANOVA) and the Bonferroni correction. The minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of nZnO were      determined using the broth microdilution method in Mueller-Hinton Agar (MHA) for S. mutans and E. faecalis, De Man, Rogosa, and Sharpe (MRS) agar, and Sabouraud Dextrose Agar (SDA). Results: The greatest inhibition zones were observed against S. mutans with 20-nm and 40-nm nZnO, while 140-nm nZnO formed the greatest inhibition zones against S. mutans and E. faecalis. The smallest inhibition zones were observed against C. albicans with the three nZnO particle sizes. The MICs for C. albicans with 40-nm and 140-nm particles and for L. fermentum with 140-nm particles were higher than 10 µg/ml. A significant correlation was found between the particle size and the antibacterial activity against S. mutans (P=0.00), L. fermentum, and E. faecalis (P<0.02).   Conclusion: The antimicrobial activity of nZnO increases with decreasing the particle size. The greatest antimicrobial effect was observed against S. mutans and E. faecalis. S. mutans is more sensitive to the changes in the particle size compared to other bacteria.

scholarly journals Categorizing susceptibility of clinical isolates of Candida auris to amphotericin B, caspofungin, and fluconazole utilizing the CLSI M44-A2 disk diffusion method

2021 ◽  
Author(s):  
Natalie S. Nunnally ◽  
Tajah Damm ◽  
Shawn R. Lockhart ◽  
Elizabeth L. Berkow
Keyword(s):  
Amphotericin B ◽  
Accurate Method ◽  
Clinical Isolates ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Broth Microdilution ◽  
Candida Auris ◽  
Disk Diffusion Method ◽  
Microdilution Method ◽  
Broth Microdilution Method

We evaluated the CLSI M44ed3E disk diffusion method in comparison with the CLSI M27ed4 broth microdilution method for caspofungin and fluconazole and the Etest method for amphotericin B to categorize susceptibility of 347 clinical isolates of Candida auris. Utilizing the zone diameter cutoffs established here we observed the overall categorial agreement between the two methods. For caspofungin, concordant results were observed for 98% of isolates with <1% very major and 1% major errors. For fluconazole, concordant results were observed for 91% of isolates with 1% very major and 8% major errors. For amphotericin B, concordant results were observed for 74% of isolates with <1% very major errors and 25% major errors. The disk diffusion approach provides an accurate method for determining the susceptibility of C. auris for caspofungin and fluconazole, and for identification of at least 75% of amphotericin B-susceptible isolates.

scholarly journals Antibacterial activity of Achillea tenuifolia Lam. extract against standard bacteria and isolated strains

2016 ◽  
Vol 2 (2) ◽  
pp. 49
Author(s):  
Sahar Omidpanah ◽  
Abbas Hadjiakhondi ◽  
Azadeh Manayi
Keyword(s):  
Room Temperature ◽  
Antimicrobial Agents ◽  
Inhibitory Concentration ◽  
Inhibition Zone ◽  
Inhibitory Effect ◽  
Diffusion Method ◽  
Disk Diffusion Method ◽  
Microdilution Method ◽  
Different Sources ◽  
Freeze Dryer

Researchers have been trying to develop new broad-spectrum antibiotics against the infectious diseases caused by bacteria, fungi, viruses, and parasites for many decades. Prolonged usage of the antibiotics has led to the emergence of drug resistance among bacteria; therefore, there is a tremendous need for novel antimicrobial agents from different sources such as plants which are used in traditional medicine. The aim of this study was to evaluate antibacterial effect of <em>Achillea tenuifolia</em>.<em> </em>The plant material was extracted by maceration method using methanol three times at room temperature. The extract was concentrated after removing the solvent by rotary evaporator and then lyophilized using freeze dryer. Inhibitory effect of the extract was examined against four standard bacteria strains and two isolated strains from diseased hen using disk diffusion method and microdilution method to evaluate their inhibition zone diameter (IZD) and minimum inhibitory concentration (MIC), respectively. The results showed that the extract of the plant was active against standard strains including <em>Escherichia coli</em>, <em>Pseudomonas aeruginosa</em>, <em>Staphylococcus aureus </em>and <em>Enterococcus faecalis </em>with IZDs of 10.3±0.5, 14±0.0, 12±0.0 and 11.6±0.5, respectively.<strong> </strong>However, growths of isolated strains were not inhibited in the presence of the extract. Although, the growths of isolated strains were not inhibited by the plant extract, the standard strains were moderately susceptible to the extract; among those <em>P. aeroginosa</em> was more sensible than other tested strains

scholarly journals Major Bloodstream Infection-Causing Bacterial Pathogens and Their Antimicrobial Resistance in South Korea, 2017–2019: Phase I Report From Kor-GLASS

2022 ◽  
Vol 12 ◽  
Author(s):  
Dokyun Kim ◽  
Eun-Jeong Yoon ◽  
Jun Sung Hong ◽  
Min Hyuk Choi ◽  
Hyun Soo Kim ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Phase I ◽  
Bloodstream Infection ◽  
Molecular Mechanisms ◽  
Diffusion Method ◽  
Disk Diffusion Method ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Glass Target ◽  
Blood Specimens

To monitor national antimicrobial resistance (AMR), the Korea Global AMR Surveillance System (Kor-GLASS) was established. This study analyzed bloodstream infection (BSI) cases from Kor-GLASS phase I from January 2017 to December 2019. Nine non-duplicated Kor-GLASS target pathogens, including Staphylococcus aureus, Enterococcus faecalis, Enterococcus faecium, Streptococcus pneumoniae, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter spp., and Salmonella spp., were isolated from blood specimens from eight sentinel hospitals. Antimicrobial susceptibility testing, AMR genotyping, and strain typing were carried out. Among the 20,041 BSI cases, 15,171 cases were caused by one of the target pathogens, and 12,578 blood isolates were collected for the study. Half (1,059/2,134) of S. aureus isolates were resistant to cefoxitin, and 38.1% (333/873) of E. faecium isolates were resistant to vancomycin. Beta-lactamase-non-producing ampicillin-resistant and penicillin-resistant E. faecalis isolates by disk diffusion method were identified, but the isolates were confirmed as ampicillin-susceptible by broth microdilution method. Among E. coli, an increasing number of isolates carried the blaCTX–M–27 gene, and the ertapenem resistance in 1.4% (30/2,110) of K. pneumoniae isolates was mostly (23/30) conferred by K. pneumoniae carbapenemases. A quarter (108/488) of P. aeruginosa isolates were resistant to meropenem, and 30.5% (33/108) of those carried acquired carbapenemase genes. Over 90% (542/599) of A. baumannii isolates were imipenem-resistant, and all except one harbored the blaOXA–23 gene. Kor-GLASS provided comprehensive AMR surveillance data, and the defined molecular mechanisms of resistance helped us to better understand AMR epidemiology. Comparative analysis with other GLASS-enrolled countries is possible owing to the harmonized system provided by GLASS.

scholarly journals In Vitro Testing of Salicylanilide Derivatives Against Some Fungal and Bacterial Strains

2019 ◽  
Vol 70 (4) ◽  
pp. 1496-1499
Author(s):  
Ioana Maria Carmen Ienascu ◽  
Diana Obistioiu ◽  
Iuliana Maria Popescu ◽  
Mariana Nela Stefanut ◽  
Osser Gyongyi ◽  
...  
Keyword(s):  
Susceptibility Testing ◽  
Inhibition Zone ◽  
Diffusion Method ◽  
Bacterial Strains ◽  
Disk Diffusion Method ◽  
Dental Office ◽  
Inhibition Zones ◽  
Benzamide Derivatives ◽  
Effective Compound

In the dental office, disinfection and sterilization are a matter of utmost importance for both the physician, the medical staff and the patient. Twelve N-(2-bromo-phenyl)-2-hydroxy-benzamide and N-(4-bromo-phenyl)-2-hydroxy-benzamide derivatives were synthesized and tested for antimicrobial activity against 6 bacterial and 2 fungal strains using the Disk diffusion method for susceptibility testing. The obtained results indicated that the N-(2-bromo-phenyl)-2-hydroxy-benzamide derivatives were more active against the tested microbes, inhibition zones of 6-12 mm being obtained, although the most effective compound against S. pyogenes proved to be N-(4-bromo-phenyl)-2-hydroxy-benzamide (14 mm inhibition zone). The tested compounds presented no effect against S. aureus, S. flexneri, S. typhimurium and C. parapsilopsis at the tested concentration.

scholarly journals Genetic Profiles and Antimicrobial Resistance Patterns of Salmonella Infantis Strains Isolated in Italy in the Food Chain of Broiler Meat Production

Antibiotics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 814
Author(s):  
Patrizia Casagrande Proietti ◽  
Valentina Stefanetti ◽  
Laura Musa ◽  
Alessia Zicavo ◽  
Anna Maria Dionisi ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Food Chain ◽  
Diffusion Method ◽  
Meat Production ◽  
Disk Diffusion Method ◽  
Broiler Meat ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Resistance Patterns ◽  
Genetic Profiles

This work aimed to evaluate the antimicrobial susceptibility of 87 Salmonella Infantis strains isolated in Italy from 2016 to 2019 along the food chain of broiler meat production and in humans and to determine the genetic profiles of the strains in order to establish a possible correlation with the antimicrobial pattern. All isolates were tested by the disk diffusion method to evaluate antimicrobial susceptibility toward sixteen antimicrobials, and the broth microdilution method was used to confirm extended spectrum β-lactamase (ESBL) production. PCR and pulsed field gel electrophoresis (PFGE) were applied to characterize ESBL-encoding and AmpC β-lactamase genes and to analyze the S. Infantis strains genetic profiles respectively. S. Infantis isolates showed high prevalence of resistance, in particular toward nalidixic acid (97.7%), tetracycline (96.5%), sulphamethoxazole/trimethoprim (91%) and cefepime (72.4%). The 80.5% of isolates were ESBL, cefotaxime-resistant, carrying the blaCTX-M1 gene. The most prevalent PFGE profile was XbaI.0126 (35.6%). The remaining strains had a genetic homology from 81% to 97% with the XbaI.0126 profile. The strains belonging to these profiles were isolated from different matrices collected along the broiler food chain independently on the year and from the region and there was no correlation between the PFGE profiles and resistance patterns. We found two ESBL-producing S. Infantis strains with the same XbaI.2621 profile isolated from humans and from poultry feces, not yet reported in Italy. Our findings confirmed the diffusion of ESBL-multi drug resistant (MDR) S. Infantis along the broiler food chain and in humans and underlined the importance of continuous monitoring to control and to reduce the prevalence of this bacterium, applying a global One Health approach.

scholarly journals Antifungal Activity of Micafungin in Serum

2009 ◽  
Vol 53 (10) ◽  
pp. 4559-4562 ◽  
Author(s):  
Jun Ishikawa ◽  
Tetsuo Maeda ◽  
Itaru Matsumura ◽  
Masato Yasumi ◽  
Hidetoshi Ujiie ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
High Performance ◽  
Diffusion Method ◽  
Broth Microdilution ◽  
Serum Samples ◽  
Disk Diffusion Method ◽  
Serum Free ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Applied Dose

ABSTRACT We have evaluated the antifungal activity of micafungin in serum by using the disk diffusion method with serum-free and serum-added micafungin standard curves. Serum samples from micafungin-treated patients have been shown to exhibit adequate antifungal activity, which was in proportion to both the applied dose and the actual concentration of micafungin measured by high-performance liquid chromatography. The antifungal activity of micafungin in serum was also confirmed with the broth microdilution method.

scholarly journals Methodological approaches to fluoroquinolone susceptibility testing of Salmonella

2020 ◽  
Vol 22 (4) ◽  
pp. 314-320
Author(s):  
Svetlana A. Egorova ◽  
L.A. Kaftyreva
Keyword(s):  
Nalidixic Acid ◽  
Susceptibility Testing ◽  
Inhibition Zone ◽  
Resistance Mechanisms ◽  
Fluoroquinolone Resistance ◽  
Diffusion Method ◽  
Repeated Testing ◽  
Disk Diffusion Method ◽  
Broth Microdilution Method ◽  
Clinical Breakpoints

Objective. To evaluate effectiveness of the various approaches to fluoroquinolone susceptibility testing of Salmonella, including S. typhi, taking into account molecular resistance mechanisms. Materials and Methods. The MIC values of ciprofloxacin were compared with the inhibition zone for pefloxacin disc, 5 mg (310 isolates) and nalidixic acid, 30 mg (420 isolates). MIC of ciprofloxacin was determined by gradient diffusion test and broth microdilution method. Muller – Hinton agar and Muller – Hinton broth, antibiotic discs and MICE-tests (Oxoid, UK) were used. Chromosomal mutations in QRDR of gyrA, gyrB, parC, and parE genes and plasmid-mediated quinolone resistance genes (qnr, aac-(6’)-1b etc.) were detected in 19 Salmonella isolates by analysis using ResFinder service (Center of Genomic Epidemiology). Genomic DNA libraries were prepared using the MiSeq Nextera XT Library Preparation Kit (Illumina, USA). WGS was performed on MiSeq (Illumina, USA) with MiSeq Reagent Kit v3 600 cycles (Illumina, USA). Genome assembly and analysis were performed using CLC Genomics Workbench 8.0 (Qiagen, USA). Results. Despite the high concordance of ciprofloxacin MIC values and the results of disc diffusion screening with pefloxacin (96.5% of isolates) and nalidixic acid (98.1% of isolates), the results obtained for some resistant isolates were inconsistent. When those isolates were tested by a single method, there was a possibility of incorrect susceptibility categorization. Discordant results were obtained for 19 isolates and had the objective reason (paradoxical resistance phenotype due to the plasmid-mediated resistance, qnrS) in 3 cases. Other discrepancies were noted when the values were equal to the clinical breakpoints: ciprofloxacin MIC – 0.06 mg/l, inhibition zone for pefloxacin – 24 mm. Repeated testing revealed the variations around the clinical breakpoints: the MIC values of 0.06–0.12 mg/l, and inhibition zone of 23 to 25 mm. Conclusions. When performing fluoroquinolone susceptibility testing of Salmonella, it is reasonable to add the category “Area of Technical Uncertainty”: ciprofloxacin MIC value of 0.06 mg/l, and inhibition zone for pefloxacin of 23 to 25 mm. Two discs (pefloxacin and nalidixic acid) should be used for fluoroquinolone resistance screening by disk diffusion method.

scholarly journals Evaluation of Disk Diffusion Method for Determining Posaconazole Susceptibility of Filamentous Fungi: Comparison with CLSI Broth Microdilution Method

2006 ◽  
Vol 50 (3) ◽  
pp. 1108-1111 ◽  
Author(s):  
E. López-Oviedo ◽  
A. I. Aller ◽  
C. Martín ◽  
C. Castro ◽  
M. Ramirez ◽  
...  
Keyword(s):  
Filamentous Fungi ◽  
Clinical Laboratory ◽  
Culture Media ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Broth Microdilution ◽  
Disk Diffusion Method ◽  
Microdilution Method ◽  
Broth Microdilution Method

ABSTRACT The disk diffusion method was evaluated for determining posaconazole susceptibility against 78 strains of molds using two culture media in comparison with the CLSI (Clinical Laboratory Standards Institute) broth microdilution method (M38-A). A significant correlation between disk diffusion and microdilution methods was observed with both culture media.

scholarly journals Evaluation of the Revised Ceftaroline Disk Diffusion Breakpoints When Testing a Challenge Collection of Methicillin-ResistantStaphylococcus aureusIsolates

2018 ◽  
Vol 56 (12) ◽  
Author(s):  
Helio S. Sader ◽  
Paul R. Rhomberg ◽  
Timothy B. Doyle ◽  
Robert K. Flamm ◽  
Rodrigo E. Mendes
Keyword(s):  
Error Rates ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Broth Microdilution ◽  
Wild Type ◽  
Disk Diffusion Method ◽  
Content Type ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Mueller Hinton Agar

ABSTRACTWe assessed ceftaroline disk diffusion breakpoints forStaphylococcus aureuswhen applying revised Clinical and Laboratory Standards Institute (CLSI) ceftaroline MIC breakpoints. Disk-MIC correlation was evaluated by testing a challenge collection (n= 158) of methicillin-resistantS. aureus(MRSA) isolates composed of 106 randomly selected isolates plus 52 isolates with decreased susceptibility to ceftaroline (MIC, 1 to 16 μg/ml). Disk diffusion was performed with 30-μg disks and Mueller-Hinton agar from 2 manufacturers each. Revised CLSI susceptible (S)/susceptible dose-dependent (SDD)/resistant (R) MIC breakpoints of ≤1/2 to 4/≥8 μg/ml were applied. The disk breakpoints that provided the lowest error rates were CLSI S/R breakpoints of ≥25 mm/≤19 mm, with no very major (VM) or major (Ma) errors and with minor (Mi) error rates of 0.0% for ≥2 doubling dilutions above the I or SDD (≥I + 2), 22.1% for I or SDD plus or minus 1 doubling dilution (I ± 1), and 2.3% for ≤2 doubling dilutions below the I or SDD ≤I − 2 (overall Mi error rate, 16.5%). No mutation in the penicillin-binding protein 2a (PBP2a) was observed in 5 of 15 isolates with a ceftaroline MIC of 2 μg/ml; 3 of 11 isolates with a ceftaroline MIC of 1 μg/ml exhibited mutations in the penicillin-binding domain (PBD; 1 isolate) or in the non-PBD (2 isolates). All isolates except 1, with a ceftaroline MIC of ≥4 μg/ml, showed ≥1 mutation in the PBD and/or non-PBD. In summary, results from the disk diffusion method showed a good correlation with those from the reference broth microdilution method. Our results also showed that the ceftaroline MIC distribution of isolates with no mutations in the PBP2a goes up to 4 μg/ml, and reference broth microdilution and disk diffusion methods do not properly separate wild-type from non-wild-type isolates.

scholarly journals Antimicrobial resistance of lactobacilli isolated from food

2013 ◽  
Vol 31 (No. 1) ◽  
pp. 27-32 ◽  
Author(s):  
M. Dušková ◽  
R. Karpíšková
Keyword(s):  
Antimicrobial Resistance ◽  
Food Industry ◽  
Meat Products ◽  
Starter Cultures ◽  
Diffusion Method ◽  
Disk Diffusion Method ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Genus Lactobacillus ◽  
Fermented Dairy

Bacteria of the genus Lactobacillus are of great benefit in many areas of life. They are widely used in food industry, in particular as part of starter cultures for fermented dairy and meat products, but also in human and veterinary medicine as probiotics. The increasing global problem of antimicrobial resistance may also involve lactic acid bacteria because of the possible risk of resistance genes transfer. We determined the antimicrobial susceptibility of lactobacilli isolated from food. Ninety facultatively heterofermentative lactobacilli isolated from retail dairy and meat products were tested. The resistance to antimicrobials was screened by the disk diffusion method and the minimum inhibitory concentrations were determined by the broth microdilution method. Fifteen strains (17%) were resistant to at least one antimicrobial agent and one strain was multiresistant.

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