scholarly journals Enterococcus faecium and Ampicillin Susceptibility Determination: Overestimation of Resistance with Disk Diffusion Method Using 2 Micrograms of Ampicillin?

2019 ◽  
Vol 57 (3) ◽  
Author(s):  
V. Joste ◽  
E. Gydé ◽  
L. Toullec ◽  
C. Courboulès ◽  
Y. Talb ◽  
...  
Keyword(s):  
Enterococcus Faecium ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Disk Diffusion Method

Enterococcus faecalis and Enterococcus faecium Isolates from Milk, Beef, and Chicken and Their Antibiotic Resistance

2003 ◽  
Vol 66 (6) ◽  
pp. 931-936 ◽  
Author(s):  
W. CHINGWARU ◽  
S. F. MPUCHANE ◽  
B. A. GASHE
Keyword(s):  
Antibiotic Resistance ◽  
Enterococcus Faecalis ◽  
Enterococcus Faecium ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Disk Diffusion Method ◽  
Predominant Species ◽  
Large Numbers ◽  
Enterococcal Species ◽  
Multiple Drugs

The occurrence and antibiotic resistance of enterococci, especially Enterococcus faecalis and Enterococcus faecium, in milk, beef, and chicken in Gaborone, Botswana, were studied. Enterococci were isolated from these sources with the use of bile esculin agar and identified with API 20 Strep kits. Antibiotic resistance was determined by the disk diffusion method. The antibiotics tested were vancomycin, teicoplanin, ampicillin, tetracycline, and cephalothin. Among the 1,467 enterococci isolated from the samples, E. faecalis (46.1%) and E. faecium (29.0%) were found to be the predominant species. Other enterococcal species made up 25% of the isolates. More than 96 and 97% of the E. faecalis and E. faecium isolates, respectively, were found to be resistant to ampicillin. Almost 34, 27.3, and 22.4% of the E. faecalis isolates from milk, beef, and chicken, respectively, were also resistant to cephalothin. The percentages of E. faecium isolates that were found to be resistant to cephalothin were 32.8, 16.9, and 17.3% for milk, beef, and chicken, respectively. Resistance to vancomycin was widespread. It was found that 18.8, 7.8, and 13.1% of the E. faecalis isolates from milk, beef, and chicken samples, respectively, were resistant to vancomycin. In contrast, 32.8, 24.7, and 30.7% of the E. faecium isolates from milk, beef, and chicken samples, respectively, were resistant to vancomycin. Isolates that were resistant to multiple drugs were found in relatively large numbers.

scholarly journals 660. Evaluation of Qvella’s FAST-Prep™ Liquid Colony™ for Early Antimicrobial Sensitivity Testing of Positive Blood Culture by Disk Diffusion Method

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S386-S386
Author(s):  
Susan M Novak-Weekley ◽  
Aye Aye Khine ◽  
Tino Alavie ◽  
Namidha Fernandez ◽  
Laxman Pandey ◽  
...  
Keyword(s):  
Direct Method ◽  
Viable Cell ◽  
Turnaround Time ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Gram Negative Bacteria ◽  
Sensitivity Testing ◽  
Gram Positive ◽  
Disk Diffusion Method ◽  
Gram Negative

Abstract Background Conventional antimicrobial susceptibility testing (AST) of microorganisms from positive blood cultures (PBC) can take ≥ 2 days. In order to improve the turnaround time for AST on a PBC, CLSI and EUCAST have made efforts to standardize procedures for disk diffusion (DD) direct from a PBC. Qvella Corporation (Richmond Hill, ON, Canada) has recently developed FAST-Prep, an automated centrifugal sample preparation system that rapidly delivers a Liquid Colony consisting of a purified, concentrated, viable cell suspension directly from a PBC. This study was performed to investigate the feasibility of DD AST off of a PBC using a FAST-Prep Liquid Colony. Methods Contrived PBC samples were prepared by spiking 6 species of Gram-positive and 4 species of Gram-negative bacteria (3-5 strains per species) into FA® Plus bottles and incubating in the BACT/ALERT® VIRTUO® System (bioMerieux, Durham, NC). After positivity, 3 mL of PBC was added to the FAST-Prep cartridge. After 20 minutes of processing in the FAST-Prep instrument, the Liquid Colony was removed from the cartridge and a 0.5 McFarland sample was prepared for DD AST. In parallel, the DD AST from a PBC was performed using 4 drops of PBC (CLSI direct method). Both methods were compared to conventional colony-based DD AST. After 16-18 hours of incubation zone diameters and S/I/R interpretations were determined. Categorical agreement (CA) and errors for both DD AST methods were calculated. In addition, colony plate counting was performed on 0.5 McFarland suspensions of Liquid Colony and the plate colony to determine biomass recovery and sample purity. Results CA for a FAST-Prep DD AST for Gram-positive and Gram-negative bacteria was 95.6% and 98.6%, respectively, compared to CA for CLSI DD AST of 77.2% and 81.9%, respectively. Biomass in the Liquid Colony was 7.2x108 and 1.2x109 CFU for Gram-positive and Gram-negative bacteria, respectively. Cell concentration in the 0.5 McFarland suspension of the Liquid Colony was 3.7x107 and 5.9x107 CFU/mL for Gram-positive and Gram-negative bacteria, respectively, which was similar to the concentration for the reference colony suspension. Conclusion The results support the potential role of FAST-Prep in providing a Liquid Colony for use in rapid AST. Disclosures Susan M. Novak-Weekley, PhD, D(ABMM), Qvella (Employee, Shareholder) Aye Aye Khine, PhD, Qvella (Employee, Shareholder) Tino Alavie, PhD, Qvella (Employee) Namidha Fernandez, MS, Qvella (Employee) Laxman Pandey, MS, Qvella (Employee) Abdossamad Talebpour, PhD, Qvella (Employee, Shareholder)

scholarly journals Evaluation of extended spectrum beta lactamase enzymes prevalence in clinical isolates of Escherichia coli

2011 ◽  
Vol 2 (1) ◽  
pp. 8
Author(s):  
Ronak Bakhtiari ◽  
Jalil Fallah Mehrabadi ◽  
Hedroosha Molla Agamirzaei ◽  
Ailar Sabbaghi ◽  
Mohammad Mehdi Soltan Dallal
Keyword(s):  
Escherichia Coli ◽  
Disk Diffusion ◽  
Confirmatory Test ◽  
Diffusion Method ◽  
Multi Drug Resistance ◽  
Beta Lactamase ◽  
Disk Diffusion Method ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Extended Spectrum

Resistance to b-lactam antibiotics by gramnegative bacteria, especially <em>Escherichia coli (E. coli)</em>, is a major public health issue worldwide. The predominant resistance mechanism in gram negative bacteria particularly <em>E. coli </em>is via the production of extended spectrum beta lactamase (ESBLs) enzymes. In recent years, the prevalence of b-lactamase producing organisms is increased and identification of these isolates by using disk diffusion method and no-one else is not satisfactory. So, this investigation focused on evaluating the prevalence of ESBL enzymes by disk diffusion method and confirmatory test (Combined Disk). Five hundred clinical samples were collected and 200 <em>E. coli </em>isolates were detected by standard biochemical tests. To performing initial screening of ESBLs was used from Disk diffusion method on <em>E. coli </em>isolates. A confirmation test (Combined Disk method) was performed on isolates of resistant to cephalosporin's indicators. Up to 70% isolates exhibited the Multi Drug Resistance phenotype. In Disk diffusion method, 128(64%) <em>E. coli </em>isolates which resistant to ceftazidime and cefotaxime while in Combined Disk, among 128 screened isolates, 115 (89.8%) isolates were detected as ESBLs producers. This survey indicate beta lactamase enzymes are playing a significant role in antibiotic resistance and correct detection of them in phenotypic test by using disk diffusion and combined Disk is essential for accurate recognition of ESBLs.

Activity of Caspofungin and Voriconazole against Clinical Isolates of Candida and Other Medically Important Yeasts by the CLSI M-44A Disk Diffusion Method with Neo-Sensitabs Tablets

Chemotherapy ◽  
2007 ◽  
Vol 54 (1) ◽  
pp. 38-42 ◽  
Author(s):  
A.J. Carrillo-Muñoz ◽  
G. Quindós ◽  
O. del Valle ◽  
P. Santos ◽  
G. Giusiano ◽  
...  
Keyword(s):  
Clinical Isolates ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Disk Diffusion Method

scholarly journals Screening commercial teat disinfectants against bacteria isolated from bovine milk using disk diffusion

2019 ◽  
Vol 12 (5) ◽  
pp. 629-637 ◽  
Author(s):  
Sarah Rose Fitzpatrick ◽  
Mary Garvey ◽  
Kieran Jordan ◽  
Jim Flynn ◽  
Bernadette O'Brien ◽  
...  
Keyword(s):  
Bacterial Species ◽  
Screening Method ◽  
Bovine Milk ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Bacterial Strains ◽  
Disk Diffusion Method ◽  
Associated Bacteria ◽  
Bacterial Inhibition ◽  
Milk Samples

Background and Aim: Teat disinfection is an important tool in reducing the incidence of bovine mastitis. Identifying the potential mastitis-causing bacterial species in milk can be the first step in choosing the correct teat disinfectant product. The objective of this study was to screen commercial teat disinfectants for inhibition against mastitis-associated bacteria isolated from various types of milk samples. Materials and Methods: Twelve commercially available teat disinfectant products were tested, against 12 mastitis-associated bacteria strains isolated from bulk tank milk samples and bacterial strains isolated from clinical (n=2) and subclinical (n=3) quarter foremilk samples using the disk diffusion method. Results: There was a significant variation (7-30 mm) in bacterial inhibition between teat disinfection products, with products containing a lactic acid combination (with chlorhexidine or salicylic acid) resulting in the greatest levels of bacterial inhibition against all tested bacteria (p<0.05). Conclusion: In this study, combined ingredients in teat disinfection products had greater levels of bacterial inhibition than when the ingredients were used individually. The disk diffusion assay is a suitable screening method to effectively differentiate the bacterial inhibition of different teat disinfectant products.

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