Comparison of disc diffusion assay with the CLSI reference method (M27-A2) for testing in vitro posaconazole activity against common and uncommon yeasts

2007 ◽  
Vol 61 (1) ◽  
pp. 135-138 ◽  
Author(s):  
E. Canton ◽  
J. Peman ◽  
A. Espinel-Ingroff ◽  
E. Martin-Mazuelos ◽  
A. Carrillo-Munoz ◽  
...  
Keyword(s):  
Reference Method ◽  
Disc Diffusion ◽  
Disc Diffusion Assay ◽  
Diffusion Assay

scholarly journals Enaminone-Derived Pyrazoles with Antimicrobial Activity

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Mashooq Ahmad Bhat ◽  
Mohamed A. Al-Omar ◽  
Ahmed M. Naglah ◽  
Abdul Arif Khan
Keyword(s):  
Antimicrobial Activity ◽  
Gram Negative Bacteria ◽  
Significant Activity ◽  
Disc Diffusion ◽  
Initial Screening ◽  
Gram Positive ◽  
Gram Negative ◽  
Disc Diffusion Assay ◽  
Gram Positive Bacteria ◽  
Diffusion Assay

A series of pyrazoles derived from the substituted enaminones were synthesized and were evaluated for antimicrobial activity. All the compounds were characterized by the spectral data and elemental analysis. The synthesized compounds were initially screened for their antimicrobial activity against ATCC 6538, NCTC 10400, NCTC 10418, and ATCC 27853. During initial screening, compounds (P1, P6, and P11) presented significant antimicrobial activity through disc diffusion assay. These compounds were further evaluated for antimicrobial activity at different time points against Gram-positive and Gram-negative bacteria and presented significant activity for 6 hours. The activity was found to be greater against Gram-positive bacteria. In contrast at 24 hours, the activity was found only against Gram-positive bacteria except compound (P11), showing activity against both types of bacteria. Compound (P11) was found to have highest activity against both Gram-positive and Gram-negative bacteria.

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.

scholarly journals Discrimination between Mycoplasma and Acholeplasma species of bovine origin using digitonin disc diffusion assay, nisin disc diffusion assay, and conventional polymerase chain reaction

2011 ◽  
Vol 24 (1) ◽  
pp. 7-13 ◽  
Author(s):  
Sukolrat Boonyayatra ◽  
Lawrence K. Fox ◽  
John M. Gay ◽  
Ashish Sawant ◽  
Thomas E. Besser
Keyword(s):  
Polymerase Chain Reaction ◽  
Growth Inhibition ◽  
Gold Standard ◽  
Conventional Polymerase Chain Reaction ◽  
Disc Diffusion ◽  
Chain Reaction ◽  
Disc Diffusion Assay ◽  
Field Isolates ◽  
Polymerase Chain ◽  
Diffusion Assay

Microbiological culture of milk samples has been used as a standard diagnosis for Mycoplasma mastitis. This technique is effective in isolating mollicutes that are Mycoplasma-like; however, isolates may be misinterpreted as Acholeplasma species, which are indistinguishable from Mycoplasma species by culture. A study to contrast the abilities of 2 culture-based tests, digitonin and nisin disc diffusion assays and a conventional polymerase chain reaction (PCR) technique, to discriminate between Mycoplasma and Acholeplasma was performed using 16S ribosomal RNA gene partial sequencing as the gold standard of comparison. A total of 288 bovine mollicute field isolates (248 from milk and 40 from other organ sites) and 13 reference strains were tested. Results obtained from the digitonin disc diffusion assay when it was performed with all field isolates were 92.7% and 99.0% in agreement with the gold standard using 5 mm and 3 mm of zone of growth inhibition as thresholds, respectively. Considering only milk isolates, agreements between the digitonin disc diffusion assay with the gold standard were 97.2% and 100% using 5 mm and 3 mm of zone of growth inhibition as thresholds, respectively. Culture identification using the nisin disc diffusion assay and the PCR was in a 100% agreement with the gold standard. Comparable results using culture-based nisin and digitonin disc diffusion assays, and PCR, to distinguish Mycoplasma and Acholeplasma species was found, especially for isolates from bovine milk.

scholarly journals Efficacy of Methanolic Leaf Extract of Hyptis suaveolens and Moringa oleifera in the Control of Soil-Borne Pathogens

2020 ◽  
pp. 56-63
Author(s):  
Okoro, Chisom Augusta ◽  
Onaebi, Chiemeka Nwakaego
Keyword(s):  
Fusarium Oxysporum ◽  
Moringa Oleifera ◽  
Biologically Active ◽  
Assay Method ◽  
Disc Diffusion ◽  
Leaf Extracts ◽  
Disc Diffusion Assay ◽  
Phytophthora Colocasiae ◽  
Hyptis Suaveolens ◽  
Diffusion Assay

Aim: Soil-borne diseases are difficult to control because they are caused by pathogens that can survive for long periods in the absence of the normal crop host and often have a wide host range including weeds. This present study was design to assess the antifungal assay dependent effect of methanolic extracts of Hyptis suaveolens and Moringa oleifera on Phytophthora colocasiae and Fusarium oxysporum. Methods: The presence of biologically active ingredients (alkaloid, saponin, tannins, flavonoid, terpenoids, tannins, steroids, hydrogen cyanides, phenols and glycoside) in the leaf extracts was investigated using standard procedures. The antifungal activities of the plant extract were tested against Phytophthora colocasiae and Fusarium oxysporum using disc and well diffusion assays. Results: The results of the phytochemical evaluated showed that H. suaveolens, contained significantly higher alkaloids, saponins, hydrogen cyanide, flavonoids and phenols than M. oleifera, while on the other hand, M. oleifera contained significantly higher terpenoids, tannins, steroids and glycosides. Consequently, H. suaveolens extract similarly recorded significantly (P < 0.05) higher inhibition on the organisms as compared to M. oleifera. The disc diffusion assay method was more sensitive than the well diffusion assay. H. suaveolens at 100 mg/ml using disc diffusion assay method showed higher inhibition on both P. colocasiae and F. oxysporum. While M. oleifera recorded higher inhibition on F. oxysporum at 50 mg/ml and P. colocasiae at 100 mg/ml using the disc diffusion assay method. MIC was lowest with H. suaveolens (12.5 mg/ml) against F. oxysporum. Conclusion: These results promote the identification of actives substances from these plants for use as lead molecules in the development of new fungicides for the control of Phytophthora colocasiae and Fusarium oxysporum.

scholarly journals Antifungal effects of 3-(4-Phenyl-thiazol-2-yl)-2-thioxo-2, 3-dihydro-1H-quinazolin-4-one against Aspergillus Species

2018 ◽  
Author(s):  
Desh D. Singh ◽  
V. K. Tiwari ◽  
Rambir Singh ◽  
G L Sharam ◽  
Rajesh Dabur
Keyword(s):  
Antifungal Activity ◽  
Protein Profile ◽  
Antifungal Drugs ◽  
Secretory Proteins ◽  
Disc Diffusion ◽  
Disc Diffusion Assay ◽  
Dilution Assay ◽  
Number Of Patients ◽  
Diffusion Assay ◽  
Microbroth Dilution

AbstractAspergillus infections have become an important health problem with the increasing number of patients. Available antifungal drugs are lack with their spectrum, toxic or immunosuppressive in nature, so that need to develop new compound with high efficacy. To evaluate antifungal efficacy of synthesized compound and to identify the protein profile of Aspergillus fumigatus treated with antifungal. Clinical isolates of A. fumigatus, A. flavus and A. niger were cultured and efficacy of compound were conducted by Disc Diffusion Assay (DDA), Microbroth Dilution Assay (MDA). Percent of spore germination inhibition assay (PSGI), Time kill analysis and toxicity assay. The culture filtrate containing secretory proteins was collected after 24 h growth and expression of downregulated proteins were identified. We developed a new and useful quinazoline derivatives expected to antifungal activity. The result of anti-Aspergillus evolution revealed that one of the 3-(4-Phenyl-thiazol-2-yl)-2-thioxo-2, 3-dihydro-1H-quinazolin-4-one (DDVKT4Q) exhibited appreciable activity. The potency of compound was found concentration of 3.125 µg/disc by disc diffusion assay (DDA) and 15.625 µg/ml. by Microbroth Dilution Assay (MDA). The compound was nontoxic up to concentration 625 µg/ml and its lysed only 35.9% of human erythrocytes, at the highest dose tested. It’s observed that the treatment of pathogen with DDVKT-4Q targeted the expression of four proteins having molecular weights 18 kDa 37 KDa and 43 KDa proteins was completely inhibited or down regulated by the compound the extra cellular. The novel compound DDVKT-4Q, having antifungal activity Can be exploited further to develop new ideal antimycotic drugs.

Comparison of Toxicity of Different Mycotoxins to Several Species of Bacteria and Yeasts: Use of Bacillus brevis in a Disc Diffusion Assay

1994 ◽  
Vol 57 (1) ◽  
pp. 48-53 ◽  
Author(s):  
M. S. MADHYASTHA ◽  
R. R. MARQUARDT ◽  
A. MASI ◽  
J. BORSA ◽  
A. A. FROHLICH
Keyword(s):  
Bacterial Species ◽  
Cyclopiazonic Acid ◽  
Inhibition Zone ◽  
Disc Diffusion ◽  
Indicator Organisms ◽  
High Concentration ◽  
Penicillic Acid ◽  
Bacillus Brevis ◽  
Disc Diffusion Assay ◽  
Diffusion Assay

Twelve species of bacteria and two species of yeast were tested for sensitivity against 11 different mycotoxins using a disc diffusion assay. Among the bacterial species, Bacillus brevis appeared to be the most sensitive microorganism, being sensitive to eight mycotoxins (AFB1, ochratoxin A [OA], citrinin [CT], patulin [PAT], penicillic acid [PA], cyclopiazonic acid [CPA], penitrem A [PT-A], and zearalenone [ZEE]). This microorganism was not affected by a high concentration (500 μg per disc) of any of the trichothecenes (T-2 toxin, HT-2 toxin, diacetoxyscirpenol, and deoxynivalenol). Kluyveromyces marxianus, a species of yeast, was the only microorganism that was inhibited by all four of the trichothecenes but was not inhibited by the other mycotoxins. The area of the inhibition zone produced by some of the mycotoxins such as OA with the B. brevis assay was dramatically influenced by the pH of the medium, while the toxicity of other mycotoxins such as AFB1 was relatively pH independent. The sensitivity of the B. brevis assay also tended to decrease at agar volumes above 6 ml and as the number of microbes per plate increased. The lowest amounts of the different ochratoxins; OA, OB and OC (OA ethyl ester) that could be detected under optimal conditions were 0.5, 20, and 2 μg per disc, respectively. The lowest amounts of CPA, AFB1 CT, PAT, PA, PT-A, and ZEE that were detectable were 0.5, 1, 1, 1, 1, 1, and 10 μg per disc, respectively. These results demonstrate that B. brevis can be used as a positive indicator organism to detect the presence of several common non-trichothecene mycotoxins. The results demonstrate that, used together, B. brevis and K. marxianus can be used as indicator organisms in a bioassay approach to the detection of several of the most common mycotoxins.

Leap forward in the treatment of Pythium insidiosum keratitis

2018 ◽  
Vol 102 (12) ◽  
pp. 1629-1633 ◽  
Author(s):  
Bhupesh Bagga ◽  
Savitri Sharma ◽  
Sai Jeevan Madhuri Guda ◽  
Ritu Nagpal ◽  
Joveeta Joseph ◽  
...  
Keyword(s):  
Antifungal Drugs ◽  
Disc Diffusion ◽  
Pythium Insidiosum ◽  
Exact Test ◽  
Number Of Patients ◽  
Lost To Follow Up ◽  
Diffusion Assay ◽  
Culture Positive

BackgroundPythium insidiosum is a parafungus that causes keratitis resembling fungal keratitis. This study compares outcome in a large cohort of patients with P insidiosum keratitis treated with antifungal drugs, to a pilot group treated with antibacterial antibiotics.MethodsBetween January 2014 and December 2016, 114 patients with culture positive P insidiosum keratitis were included in the study. A subset of culture isolates was tested in vitro for response to nine antibacterial antibiotics by disc diffusion and E test. Patients were treated with topical natamycin in 2014, 2015 and up until mid 2016. Thereafter, the patients received a combination of topical linezolid and topical and oral azithromycin. Therapeutic penetrating keratoplasty (TPK) was done for patients not responding to medical therapy.ResultsIn vitro disc diffusion assay showed linezolid to be most effective. The rate of TPK was significantly higher in 2015 compared with 2016 (43/45, 95.6% vs 22/32, 68.8%; p=0.002). Eighteen patients were treated with antibacterial and 14 were treated with antifungal antibiotic in 2016. One patient was lost to follow-up in each group. The rate of TPK was higher and proportion of healed ulcers was lower (p=0.21, Fisher’s exact test) in the group on antifungal therapy (TPK—11/13, 84.6%; Healed—2/13, 15.3%) compared with the group on antibacterial therapy (TPK—11/17, 64.7%; Healed—6/17, 35.2%).ConclusionsWe report favourable but not statistically significant response of P insidiosum keratitis to antibacterial agents in a pilot series of patients. Further evaluation of this strategy in larger number of patients is recommended.

scholarly journals In vitro Assessment of Bacterial Strains Associated with Microalgae as Potential Probiotics

2021 ◽  
Vol 44 (1) ◽  
Author(s):  
Aimi Zabidi ◽  
Natasya-Ain Rosland ◽  
Jasmin Yaminudin ◽  
Murni Karim
Keyword(s):  
Antimicrobial Activity ◽  
In Vitro Assays ◽  
Disc Diffusion ◽  
Bacterial Strains ◽  
Pathogenic Vibrio ◽  
Fish And Shellfish ◽  
Diffusion Assay ◽  
Vibrio Spp

Bacteria and microalgae are essential elements in the aquatic ecosystem, co-existing and having constant interactions with each other which help microalgae to exert its beneficial effect as probiotics in aquaculture. This research aims to isolate and identify potential probiotics from different species of microalgae and to evaluate their antimicrobial activity against pathogenic Vibrio spp. via series of in vitro assays; disc diffusion, well diffusion, and co-culture assays. A total of 18 bacterial strains were isolated from five species of microalgae; Chlorella sp., Nannochloropsis sp., Amphora sp., Chaetoceros sp., and Spirulina sp.. The isolated strains were tested in in vitro antagonistic assay against four Vibrio spp. (Vibrio harveyi, Vibrio alginolyticus, Vibrio vulnificus, and Vibrio parahaemolyticus). Seventeen strains demonstrated antimicrobial activity with the highest inhibition was observed by strain SPS11 against V. parahaemolyticus (12.6 ± 0.36 mm) in disc diffusion assay and strain NAS32 showed 13.2 ± 0.45 mm clear zone against V. vulnificus in well diffusion assay. In co-culture assay, both the SPS11 and NAS32 were able to reduce the growth of V. parahaemolyticus and V. harveyi at concentration of 106 and 108 CFU mL-1, respectively. Strains SPS11 and NAS32 were characterized as gram positive bacteria with rod shape and further identified as Lysinibacillus fusiformis (SPS11) and Lysinibacillus sphaericus (NAS32) using 16s rRNA. These two strains should be further studied in in vivo challenged experiments in fish and shellfish to explore their probiotic effects.

Sign in / Sign up

Export Citation Format

Share Document