Quantitative determination of echinomycin by disc agar diffusion assay

1982 ◽  
Vol 15 (2) ◽  
pp. 104-110 ◽  
Author(s):  
D. Gauvreau ◽  
M. J. Waring
Keyword(s):  
Quantitative Determination ◽  
Agar Diffusion ◽  
Agar Diffusion Assay ◽  
Diffusion Assay

Quantitative determination of antibiotics by automated six-point parallel-line agar diffusion assay

1974 ◽  
Vol 40 (4) ◽  
pp. 610-611 ◽  
Author(s):  
D. A. Detmar ◽  
K. H. F. van Hemert ◽  
R. Malherbe ◽  
J. G. Oostendorp
Keyword(s):  
Quantitative Determination ◽  
Parallel Line ◽  
Agar Diffusion ◽  
Agar Diffusion Assay ◽  
Diffusion Assay

CAS agar diffusion assay for the measurement of siderophores in biological fluids

2001 ◽  
Vol 44 (1) ◽  
pp. 89-95 ◽  
Author(s):  
Sung Heui Shin ◽  
Yong Lim ◽  
Shee Eun Lee ◽  
Nam Woong Yang ◽  
Joon Haeng Rhee
Keyword(s):  
Biological Fluids ◽  
Agar Diffusion ◽  
Agar Diffusion Assay ◽  
Diffusion Assay

Novel Quantitative Assays for Estimating the Antimicrobial Activity of Fresh Garlic Juice†,‡

2001 ◽  
Vol 64 (2) ◽  
pp. 189-194 ◽  
Author(s):  
R. UNAL ◽  
H. P. FLEMING ◽  
R. F. McFEETERS ◽  
R. L. THOMPSON ◽  
F. BREIDT ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Dose Response ◽  
Ratio Method ◽  
E Coli ◽  
Agar Diffusion ◽  
Dilution Assay ◽  
Agar Diffusion Assay ◽  
Slope Ratio Method ◽  
Diffusion Assay ◽  
Broth Dilution

Novel agar diffusion and broth dilution assays were developed for quantitatively estimating the antimicrobial activity of fresh garlic juice. Bacteria found to be inhibited by garlic juice in agar diffusion assay included two gram-positive and five gram-negative species. Leuconostoc mesenteroides was not inhibited. Escherichia coli B-103 (HB101, with pJH101, ampicillin resistant, 100 μg ml−1) was inhibited and chosen as the standard culture for quantitative assays. The agar diffusion assay was based on the slope ratio method, where the slope of dose response for garlic juice was divided by the slope of dose response for methylmethane thiosulfonate (MMTSO2). Juice from fresh garlic varied in activity between 1.76 and 2.31 μg of MMTSO2 per mg of garlic juice. The activity of juice decreased during 11 months of storage of garlic cloves at 5°C from 2.31 to less than 0.1 μg of MMTSO2 per mg of juice. The broth dilution assay also used the E. coli B-103 culture, which permitted selective enumeration of this bacterium when 100 μg ml−1 of ampicillin was incorporated into the enumerating agar. Selective enumeration was essential since the garlic juice was not sterile and, thus, contained natural flora. Growth of E. coli was unaffected by 0.1%, delayed by 0.25%, and completely inhibited at 0.5 and 2% garlic juice in broth during 24 h of incubation at 37°C. The minimum inhibition concentration of garlic juice by broth dilution assay was, thus, estimated to be 0.5%, which is equivalent to 3.46 μg of MMTSO2 per mg of garlic juice by the agar diffusion assay.

scholarly journals Colistin and Isavuconazole Interact Synergistically In Vitro against Aspergillus nidulans and Aspergillus niger

2020 ◽  
Vol 8 (9) ◽  
pp. 1447
Author(s):  
Patrick Schwarz ◽  
Elie Djenontin ◽  
Eric Dannaoui
Keyword(s):  
Aspergillus Niger ◽  
Aspergillus Nidulans ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Important Species ◽  
Agar Diffusion ◽  
Agar Diffusion Assay ◽  
Diffusion Assay

The in vitro interactions of isavuconazole in combination with colistin were evaluated against 55 clinical Aspergillus species isolates belonging to the five most important species (Aspergillus flavus, Aspergillus fumigatus, Aspergillus nidulans, Aspergillus niger, and Aspergillus terreus) responsible for human aspergillosis by a microdilution checkerboard technique based on the European Committee on Antimicrobial Susceptibility Testing (EUCAST) reference method for antifungal susceptibility testing. Selected isolates (A. nidulans, n = 10; A. niger, n = 15) were additionally evaluated by an agar diffusion assay using isavuconazole gradient concentration strips with or without colistin incorporated Roswell Parc Memorial Institute (RPMI) agar. Interpretation of the checkerboard results was done by the fractional inhibitory concentration index. Using the checkerboard method, combination isavuconazole–colistin was synergistic for 100% of the 15 A. nidulans isolates and for 60% of the 20 A. niger isolates. No interactions were found for any of the other isolates. By agar diffusion assay, minimal inhibitory concentrations (MICs) in combination decreased compared to isavuconazole alone for 92% of the isolates. No interactions were found for any A. nidulans isolates, but synergy was observed for 40% of the A. niger isolates. A poor essential agreement of EUCAST and gradient concentration strip MICs at ± 2 log2 dilutions with 0% was obtained. Antagonistic interactions were never observed regardless of the technique used.

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