4,504 research outputs found
In vitro biofilms and antifungal susceptibility of dermatophyte and non-dermatophyte moulds involved in foot mycosis
Tinea pedis and onychomycosis are among the commonest fungal diseases in the world. Dermatophytes and, less frequently, non-dermatophyte moulds are aetiological agents of foot mycosis and are capable of forming biofilms. Fungal biofilm has demonstrated increasing drug resistance. This work aims to evaluate, in vitro, the ability to form biofilm and the susceptibility to antifungal drugs of sessile dermatophytes and non-dermatophyte moulds involved in foot mycosis. Thirty-six dermatophytes and non-dermatophyte moulds isolated from Tunisian patients with foot mycoses, and identified with MALDI-TOF have been tested. MICs of fluconazole, econazole, itraconazole, terbinafine and griseofulvin were carried out using CLSI broth microdilution method. The ability to form biofilm and antifungal activities of drugs against fungal biofilm formation has been quantified by Crystal Violet and Safranin Red staining. Biomass quantification revealed that all species studied were able to form biofilms in vitro after 72 hours. Fluconazole, econazole, itraconazole and terbinafine inhibited fungal growth with MIC values ranging from 0.031 to >64 μg mL(-1) . The best antifungal activity has been obtained with terbinafine against Fusarium solani. Econazole showed the highest activity against fungal biofilm formation. These findings can help clinicians to develop the appropriate therapy of foot mycosis
Antimicrobial susceptibility testing of dermatophytes - Comparison of the agar macrodilution and broth microdilution tests
Fifty dermatophyte strains, recently obtained from clinical material, belonging to 4 different species were examined for their susceptibility to 5 systemic or topical antimycotic agents using both an agar macrodilution and a broth microdilution test. Antimycotics compared were griseofulvin, itraconazole, sertaconazole, terbinafine and ciclopiroxolamine. A comparison of the minimum inhibitory concentrations (MIC) clearly showed differences between the two test methods applied. For all 5 antimycotics, MIC data were three- to seventyfold lower in the microdilution test system. These differences, depending on the test method, have to be taken into account when comparing MIC data in the literature or when relating the in vitro data to the tissue concentrations determined in vivo
Dermatophytes’ identification by Matrix-assisted laser desorption ionization-time of flight mass spectrometry. (MALDI-TOF MS) - the experience of a clinical laboratory
Objectives:
Dermatophytes are a challenging group of fungi that infect the keratinized tissues. The taxonomy of these
fungi has changed recently with the reclassification of some species and description of new ones. However,
many clinical laboratories still base the identification of dermatophytes on their phenotype. Since
dermatophytes are very pleomorphic, macro and micromorphology are often insufficient to reach a correct
classification and may lead to misidentifications. The identification based on MALDI-TOF relies on the protein
profile of the microorganism. Thus, this study aims to summarize our current laboratorial experience of
dermatophyte identification using MALDI-TOF MS.
Methods:
From january to april 2018, 95 dermatophytes isolates, collected from human keratinized samples and also
from quality control programs were characterized by phenotypic analysis, and by VITEK MS V3.2 bioMerieux.
Before identification procedure, isolates were inoculated on Sabouraud Dextrose agar plates and incubated at
27°C during 5 to 10 days. Species were identified taking into account clinical features, as well as cultural,
microscopic and physiological characteristics. Prior to MALDI-TOF MS analysis, the samples were pre-treated
according to the manufacturer’s protocol for filamentous fungi. Molecular identification by sequencing of the
internal transcribed spacer 1 (ITS1) was performed in 34 of those isolates
Results:
Through phenotypic analysis eight different species were identified (54 Trichophyton rubrum; 4 T.soudanense;
22 T.interdigitale; 1 T.mentagrophytes; 3 T.tonsurans; 7 Microsporum canis; 3 M.audouinii; 1 Microsporum
spp.- (non canis or audouinii). MALDI-TOF analysis showed an identification agreement in 80 cases (84,2%)
with a confidence level of 99,9%. Eight isolates showed divergent identification results: three T.rubrum were
identified as T.violaceum, three T.soudanense were identified as T.rubrum, one T.mentagrophytes was
identified as T.interdigitale and one T.tonsurans was identified as T.rubrum. In four cases MALDI-TOF analysis
did not get a profile. The ITS sequencing analysis of discrepant results corroborated the MALDI-TOF
identification in five of them. On the other hand, T.soudanense was only identified by phenotypic analysis since
MALDI-TOF and ITS sequencing result was T.rubrum. MALDITOF identification of T.violaceum was not
confirmed by ITS sequencing that identified T. rubrum instead, in accordance with the phenotypic
identification.
Conclusion:
Correct identification of dermatophytes to species level requires sequencing of the ITS, LSU, and/or betatubulin
regions. The implementation of this methodology in a clinical laboratory is expensive and time
consuming. MALDI-TOF identification is a good option for dermatophytes’ identification performed in
laboratory routine, since costs of consumables as well as time of sample preparation are lower than for PCR
analysis and doesn’t require long training period as phenotypic identification does. In this study, however, both
methods failed to identify some species variants like Trichophyton soudanense or T. violaceum. The combined
use of both MALDI-TOF and phenotypic methods seems to be the better approach for dermatophytes’
identification since some species show significant phenotypic and clinical differences.info:eu-repo/semantics/publishedVersio
Tinea capitis due to Trichophyton tonsurans in a Maltese patient
We report a case of tinea capitis caused by Trichophyton tonsurans in a 16-year-old male. This appears to be the first documented case of tinea capitis caused by this dermatophyte in a native Maltese patient.peer-reviewe
Tinea pedis: diagnosis and management
Tinea pedis is one of the most commonly encountered foot infections. The fact that in most cases it is easily treatable yet still prevalent in the general population suggests it is often undiagnosed or remains untreated by health care professionals and patients. The most common agent is Trichophyton rubrum which is often mistaken for dry skin in its presentation. Treatment should include curative as well as preventative measures where possible
Fungicidal activity plus reservoir effect allow short treatment courses with terbinafine in tinea pedis
Terbinafine, a synthetic allylamine, exerts fungicidal activity against dermatophytes, the causative pathogens of tinea pedis. As proven in numerous clinical trials, tinea pedis can be effectively and safely treated by topical terbinafine. In fact, a 1-week application of terbinafine 1% cream eradicated fungal pathogens at least as effectively as 4-week treatment courses with topical azole derivative antifungals and showed lower relapse rates. A new innovative single-application formulation of terbinafine 1% in a film-forming solution produces a high concentration gradient on the skin surface and enables a prolonged (up to 13 days) exposure of the skin to terbinafine. High drug penetration into the skin results in an otherwise not obtained drug reservoir in the horny layer, the location of dermatophytes in tinea pedis. Although azole antimycotics can also effectively penetrate into the horny layer of the skin, short-term therapy might not be feasible due to its primarily fungistatic activity against dermatophytes. Thus, we conclude that the high efficacy of short-term treatment with terbinafine in patients with tinea pedis is possible due to its fungicidal activity coupled with a distinct reservoir formation in the upper layers of the epidermis. Copyright (C) 2008 S. Karger AG, Basel
Chronic dermatomycoses of the foot as risk factors for acute bacterial cellulitis of the leg: A case-control study
Objective: To assess the role of foot dermatomycosis ( tinea pedis and onychomycosis) and other candidate risk factors in the development of acute bacterial cellulitis of the leg. Methods: A case-control study, including 243 patients ( cases) with acute bacterial cellulitis of the leg and 467 controls, 2 per case, individually matched for gender, age (+/-5 years), hospital and admission date (+/-2 months). Results: Overall, mycology-proven foot dermatomycosis was a significant risk factor for acute bacterial cellulitis (odds ratio, OR: 2.4; p < 0.001), as were tinea pedis interdigitalis (OR: 3.2; p < 0.001), tinea pedis plantaris (OR: 1.7; p = 0.005) and onychomycosis (OR: 2.2; p < 0.001) individually. Other risk factors included: disruption of the cutaneous barrier, history of bacterial cellulitis, chronic venous insufficiency and leg oedema. Conclusions: Tinea pedis and onychomycosis were found to be significant risk factors for acute bacterial cellulitis of the leg that are readily amenable to treatment with effective pharmacological therapy. Copyright (C) 2004 S. Karger AG, Basel
Studies of proteinograms in dermatophytes by disc electrophoresis. 1. Protein bands in relation to growth phase
Homogenates were prepared from various growth phases of Microsporum gypseum grown on different amino acids as the nitrogen source. When analyzed on 7.5% polyacrylamide disc gels, the water-soluble proteins in these homogenates gave essentially identical banding patterns
- …