Showing 6 results for Shams-Ghahfarokhi
Volume 4, Issue 3 (Summer 2018)
Abstract
Aims: Transportation of clinical samples and long-term recoverability of fungal strains are critical to epidemiological studies. In addition, the study of fungi often requires the use of living pure cultures. The aim of this study was to evaluate the methods used to preserve culture collections of dermatophytes, consisted of storage in sterile distilled water, cryopreservation with glycerol, preserving in tryptic soy broth (TSB), and freezing mycobiotic agar.
Materials and Methods: in this experimental study, ninety-two dermatophyte isolates belonged to 10 species were tested. The freezing protocol was done in 4 forms of sterile distilled water, cryopreservation with glycerol, freezing mycobiotic agar, and preserving in TSB. The viability of the dermatophytes species was assessed after 3 years at morphological (macro and microscopic features), physiological (Using Dermatophyte Test Medium; DTM, urease test media, and the hair perforation test), and genetic levels by restriction fragment length polymorphism (RFLP).
Findings: The survival rate was 84 out of 92 water stored fungal strains (91.3%) and 81 out of 92 mycobiotic agar stored strains (88.0%) and 75 out of 92 glycerol 40% stored strains (81.5%) and 43 out of 92 TSB stored fungal strains (46.7%). Overall, more than 88% of the strains survived in the distilled water storage and freezing mycobiotic agar, methods, while storage in TSB had the least success in the maintenance of dermatophytes.
Conclusion: The procedure to preserve cultures in sterile distilled water is reliable, simple, and inexpensive.
Volume 6, Issue 4 (Fall 2020)
Abstract
Background: Aureobasidin A is known as a cyclic depsipeptide antibiotic with toxic effects against yeasts such as Candida spp at low concentration. Combination therapy is used as a conventional treatment for fungal infections, especially drug-resistant cases. The current study aimed to investigate the combined effects of fluconazole and Aureobasidin A on fluconazole-resistant C. albicans isolates using broth microdilution method.
Materials & Methods: Antifungal activity of Aureobasidin A (AbA) compared to fluconazole against C. albicans ATCC 76615 strain was determined using the standardized broth microdilution method according to the Clinical and Laboratory Standards Institute (CLSI, document M27-Ed4) guidelines. The checkerboard method was used to test the combined effects of Aureobasidin A and fluconazole. The synergy, indifference, and antagonism were defined based on the fractional inhibitory concentration values below 0.5, 0.5-4, and more than 4 μg/mL, respectively.
Findings: MIC50 and MIC90 evaluations of Aureobasidin A and fluconazole were done at concentrations of 0.25-2 and 32-64 μg/mL against C. glabrata isolates, respectively. The synergy between fluconazole and Aureobasidin A was observed against Candida isolate. A reduced MIC was demonstrated against C. albicans isolate when fluconazole was combined with Aureobasidin A at 4 to 0.12 μg/mL concentrations.
Conclusion: The present study findings revealed that Aureobasidin A combined with fluconazole exhibited potent inhibitory effects against fluconazole-resistant C. albicans isolates. Further studies is recommended to investigate the synergistic effects of Aureobasidin A and other antifungal drugs.
Volume 8, Issue 1 (Winter 2022)
Abstract
Backgrounds: Aspergillus fumigatus is a pathogen responsible for invasive aspergillosis and the main leading cause of death in immunosuppressed individuals. The present study aimed to evaluate the impact of eugenol-loaded chitosan nanoparticles on the expression of CYP51a and CYP51b, two well-known genes responsible for triazole drug resistance in A. fumigatus.
Materials & Methods: The minimum inhibitory concentration (MIC) of eugenol-loaded chitosan nanoparticles, chitosan, eugenol, and itraconazole was determined based on the Clinical and Laboratory Standards Institute M38-E3 method at concentrations of 4.6-2400, 11.7-12000, 2-2048, and 1-256 μg/mL, respectively. The expression of CYP51A and CYP51B was evaluated in A. fumigatus exposed to 0.5, 1, and 2× of MIC concentration of NPs and itraconazole using the real-time polymerase chain reaction.
Findings: The obtained results showed that eugenol-loaded chitosan nanoparticles sucessfully reduced A. fumigatus fungal growth at 300 μg/mL concentration. MIC of chitosan, eugenol, and itraconazole was measured to be 6000, 256, and 4 μg/mL, respectively. The results of real-time PCR also revealed that eugenol-loaded chitosan nanoparticles increased the expression of both CYP51A and CYP51B in a dose-dependent manner. The expression of fungal CYP51A and CYP51B at mRNA level was significantly increased 1.26, 1.93, and 3.1-fold as well as 1.2, 2.1, and 2.4-fold at concentrations of 150, 300, and 600 μg/mL, respectively (p<.05). However, it seems that the prepared nanoparticles had a lower impact on the expression of these genes compared to itraconazole.
Conclusion: Overall, these findings suggest that the treatment of A. fumigatus with eugenol-chitosan nanoparticles could increase the expression of the CYP51 gene, suggesting the anti-fungal property of these nanoparticles.
Volume 8, Issue 2 (Spring 2022)
Abstract
Backgrounds: Allium cepa L. as a traditional medicine is a rich source of beneficial bioactive metabolites. In the present study, the effect of A. cepa ethanolic extract (EAC) was studied on Aspergillus fumigatus growth, ergosterol synthesis, gliotoxin production, and gliP gene expression.
Materials & Methods: The minimum inhibitory concentration (MIC) of EAC (125-4000 µg/mL) was determined against A. fumigatus isolates according to Clinical and Laboratory Standards Institute (CLSI) guidelines (M-38). Protease activity, gliotoxin production, cell membrane ergosterol content, ultrastructure, and gliP gene expression were evaluated in the fungus exposed to 0.5× MIC concentrations of EAC (1000 μg/mL) and fluconazole (FCZ: 64 μg/mL).
Findings: Ergosterol content was significantly reduced to 0.53 and 0.45 µg/mg in FCZ- and EAC-treated fungal cells, respectively (p< .001). The protease activity was significantly inhibited in both EAC- and FCZ-treated groups. The gliotoxin production was inhibited by 51.55 and 68.75% in the treated groups with FCZ and EAC, respectively. The expression of gliP in both EAC- and FCZ-treated A. fumigatus groups was significantly reduced by 0.40 and 0.53-fold, respectively (p< .05).
Conclusion: This study finding revealed that A. cepa ethanolic extract (EAC) effectively suppressed the growth and virulence factors of A. fumigatus, which could be attributed in part to its bioactive metabolites. Further studies are recommended to isolate and identify these metabolites as potential candidates for the development of antifungal drugs.
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Volume 16, Issue 2 (9-2013)
Abstract
Objective: The prevalence of respiratory allergies, especially those induced by fungi such as Alternaria alternata, has dramatically increased over the past decade. This increase has caused major health problems worldwide. This study aimed to investigate the role of A. alternata in the etiology of allergic asthma, by using the skin prick test and assessment of IgE specific to the fungus in the patient's sera. Methods: This study enrolled 202 patients with allergic asthma, aged 12 to 83 years. Participants included 40.1% males and 59.9% females who were enrolled after recording demographic information. A skin prick test with the whole cellextract of A. alternata was performed on the epidermis of the patients' forearms. Histamine and normal saline were used as positive and negative controls, respectively. Serum levels of IgE specific for A. alternata were measured for all patients using the ImmunoCAP Phadiatop method in which the specific A. alternata allergen cocktail that connected to the solid phase reacted to IgE antibodies in each patient's sera. Data were analyzed by analysis of variance and chi-square tests. Results: Among 202 patients with allergic asthma, 14 (6.93%) had mild asthma, 73 (36.10%) were moderate asthmatics and 115 (56.90%) had severe asthma. In total, 14 (6.93%) patients were positive for both the skin test and IgE specific to A. alternata, 35 (17.33%) had negative specific IgE and positive skin test results, and 36 (17.82%) had a positive specific IgE and negative skin test. A total of 117 (57.92%) patients were negative for both tests. Conclusion: The results of this study showed the presence of IgE specific for A. alternata in 50 of 202 (24.75%) patients diagnosed with allergic asthma. The skin prick test was successfully used as a screening test. The results were further confirmed by solid-phase immunoassay of the IgE specific for A. alternata crude allergenic extract.
Volume 16, Issue 3 (12-2013)
Abstract
Objective: Fusarium species are prevalent contaminants of foodstuffs and agricultural crops. They produce fumonisins, which are carcinogenic mycotoxins. The present study has evaluated maize and wheat samples from ten provinces in Iran that were contaminated with Fusarium species. Special attention was paid to the ability of the isolates to produce fumonisin B1 (FB1) as a public health hazard.
Methods: We collected 32 maize and 15 wheat samples from ten provinces that were major cultivation areas. Samples surface disinfected with a 1% sodium hypochlorite solution for 2 minutes. Fusarium species were isolated by the flotation method on malachite green agar. Pure cultures on potato dextrose agar (PDA) were identified using a combination of macroscopic and microscopic morphological criteria. The ability of the isolates to produce FB1 was evaluated by thin layer chromatography (TLC) and the amounts of fumonisin B1 produced were assessed by high performance liquid chromatography (HPLC).
Results: A total of 55 Fusarium isolates that belonged to five species were isolated. There were 27 of the 32 maize samples (84.4%) and 11 of 15 wheat samples (73.3%) that were contaminated with Fusarium species. Species consisted of F. verticillioides (23 isolates), F. proliferatum (22 isolates), F. subglutinans (5 isolates), F. nygamai (4 isolates) and F. redolens (1 isolate) based on morphological criteria. Twenty-two of the 55 (40%) Fusarium isolates produced FB1 in a total range from 230.4 to 9565 µg/ml. The highest amounts of FB1 production were related to toxigenic isolates of F. verticillioides and F. proliferatum.
Conclusion: Results of the present work indicates a high degree of contamination of maize and wheat with Fusarium strains that belong to the Gibberella fujikuroi species complex وparticularly F. verticillioides and F. proliferatum. This contamination is a potential public health threat due to food spoilage and subsequent production of high levels of carcinogenic FB1.
