Factors influencing susceptibility testing of antifungal drugs: a critical review of document M27-A4 from the Clinical and Laboratory Standards Institute (CLSI)

Sousa, Edinaira Sulany Oliveira de; Cortez, Ana Cláudia Alves; Melhem, Márcia de Souza Carvalho; Frickmann, Hagen; Souza, João Vicente Braga de

doi:10.1007/s42770-020-00354-6

Cited by 18 publications

(12 citation statements)

References 58 publications

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“…The antifungal activity was evaluated according to the method used by Khalil et al [ 45 ], with modifications. Additionally, the minimum inhibitory concentration (MIC) for each extract was determined using the broth micro-dilution method [ 105 ]. Initially, 100 μL of broth medium was added in a 96-well plate.…”

Section: Methodsmentioning

confidence: 99%

Enhancement of Seawater Stress Tolerance in Barley by the Endophytic Fungus Aspergillus ochraceus

et al. 2021

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Symbiotic plant-fungi interaction is a promising approach to alleviate salt stress in plants. Moreover, endophytic fungi are well known to promote the growth of various crop plants. Herein, seven fungal endophytes were screened for salt tolerance; the results revealed that Aspergillus ochraceus showed a great potentiality in terms of salt tolerance, up to 200 g L−1. The indole acetic acid (IAA) production antioxidant capacity and antifungal activity of A. ochraceus were evaluated, in vitro, under two levels of seawater stress, 15 and 30% (v/v; seawater/distilled water). The results illustrated that A. ochraceus could produce about 146 and 176 µg mL−1 IAA in 15 and 30% seawater, respectively. The yield of IAA by A. ochraceus at 30% seawater was significantly higher at all tryptophan concentrations, as compared with that at 15% seawater. Moreover, the antioxidant activity of ethyl acetate extract of A. ochraceus (1000 µg mL−1) at 15 and 30% seawater was 95.83 ± 1.25 and 98.33 ± 0.57%, respectively. Crude extracts of A. ochraceus obtained at 15 and 30% seawater exhibited significant antifungal activity against F. oxysporum, compared to distilled water. The irrigation of barley plants with seawater (15 and 30%) caused notable declines in most morphological indices, pigments, sugars, proteins, and yield characteristics, while increasing the contents of proline, malondialdehyde, and hydrogen peroxide and the activities of antioxidant enzymes. On the other hand, the application of A. ochraceus mitigated the harmful effects of seawater on the growth and physiology of barley plants. Therefore, this study suggests that the endophytic fungus A. ochraceus MT089958 could be applied as a strategy for mitigating the stress imposed by seawater irrigation in barley plants and, therefore, improving crop growth and productivity.

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Section: Methodsmentioning

confidence: 99%

Enhancement of Seawater Stress Tolerance in Barley by the Endophytic Fungus Aspergillus ochraceus

et al. 2021

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“…The determination of the minimum inhibitory concentration (MIC) was performed following the Clinical and Laboratory Standards Institute guidelines for yeast broth dilution antifungal susceptibility testing [ 11 , 12 ]. The fungal growth was assessed by measuring the absorbance data at 620 nm using a spectrophotometer (Multiscan GO, Thermo Fisher Scientific, Waltham, MA, USA).…”

Section: Methodsmentioning

confidence: 99%

2,4-Diacetylphloroglucinol Modulates Candida albicans Virulence

Stepanov

Poshvina

Vasilchenko

2022

JoF

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The dimorphic fungus Candida albicans is one of the most important opportunistic pathogens for humankind. The use of fungicides against Candida could be associated with sub-inhibitory effects, which are referred to as fungal stress responses and are undesirable for the host. In this work, we investigated the antifungal action of 2,4-diacetylphloroglucinol (2,4-DAPG) against Candida albicans ATCC 10231 with a focus on their biofilm-forming ability. We found that 2,4-DAPG was able to reduce the ability of Candida cells to form biofilms, but complete inhibition and eradication effects were not achieved. Furthermore, C. albicans cells in the adherent state were characterized by reduced susceptibility to 2,4-DAPG compared to planktonic cells. The investigation of the mechanisms that could explain the antibiofilm action of 2,4-DAPG revealed a reduction in the cell`s surface hydrophobicity and the inhibition of the yeast-to-hyphae transition. The inhibition of the Candida cells filamentation was accompanied by an increase in the expression of the NRG1 gene, which is a negative regulator of hyphal development. In addition, we microscopically visualized the treated biofilms and revealed numerous channels that were decorated with particles and localized on the hyphae. We assumed that these hyphal structures could be associated with the secretion of aspartyl proteases (Sap). The performed assessments revealed an increase in the activity of Sap, which was accompanied by an increase in the expression of the sap2 and sap4 genes. The antifungal action of 2,4-DAPG is known to be associated with affecting the permeability of cellular structures, which leads to H+ATPase malfunction and the disruption of mitochondrial respiration. The subsequent cytosol acidification and generation of ROS trigger the inhibition of Candida filamentation and activation of Sap production. The introduction of antioxidant Trolox simultaneously with 2,4-DAPG leads to a reduction in Sap production. Collectively, the obtained data indicate new aspects of the interaction of fungal cells with 2,4-DAPG, an antimicrobial metabolite of Pseudomonas spp.

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“…Determination of minimal inhibitory concentration (MIC) was performed following the Clinical and Laboratory Standards Institute guidelines for broth dilution antifungal susceptibility testing of yeasts (de Sousa et al 2020; CLSI M27 document). The MIC was determined as the lowest concentration of antibiotic for which no visible fungal growth could be observed after 24 h of incubation.…”

Section: Methodsmentioning

confidence: 99%

2,4-Diacetylphloroglucinol Against Candida albicans: Biofilm Formation, Aspartyl Protease Production and Ultrastructure Changes

Stepanov

Vasilchenko

2022

Preprint

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The dimorphic fungus Candida albicans is the one of the most important opportunistic pathogen of human. The use of fungicides against candida encounters sub-inhibitory effects, which are fungal stress response and undesirable for the host. In this work we investigated antifungal action of 2,4-diacetylphloroglucinol against Candida albicans ATCC 10231 with focus on they biofilm forming ability under the treatment.It was found that 2,4-DAPG reduced ability of candida cells to form biofilm, but complete inhibition or irradiation did not achieve. Moreover, Candida albicans cells in the adherent state have been characterized by reduced susceptibility to 2,4-DAPG comparing to planktonic cells.Investigation of mechanisms which could be explain the antibiofilm action of 2,4-DAPG has revealed the reduction in cell’s surface hydrophobicity and inhibition of yeast-to-hyphae transition. Biofilms formed under the sub-inhibitory concentrations of 2,4-DAPG were depleted in protein and carbohydrate content. Furthermore, we microscopically visualized the treated biofilms and have revealed numerous cannels localized on hyphae and associated with secretion of aspartyl proteases (Sap).We assumed what excretion of Sap is triggered by reactive oxygen generated upon affecting of mitochondrion respiration by 2,4-DAPG. Introducing of antioxidant Trolox simultaneously with 2,4-DAPG lead to reducing of Sap production. Thus, production of aspartyl proteases is a one of undesirable side effect of Candida albicans treatment, but using 2,4-DAPG in combination with antioxidants is the solution to overcome it.

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Factors influencing susceptibility testing of antifungal drugs: a critical review of document M27-A4 from the Clinical and Laboratory Standards Institute (CLSI)

Cited by 18 publications

References 58 publications

Enhancement of Seawater Stress Tolerance in Barley by the Endophytic Fungus Aspergillus ochraceus

Enhancement of Seawater Stress Tolerance in Barley by the Endophytic Fungus Aspergillus ochraceus

2,4-Diacetylphloroglucinol Modulates Candida albicans Virulence

2,4-Diacetylphloroglucinol Against Candida albicans: Biofilm Formation, Aspartyl Protease Production and Ultrastructure Changes

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