Farzad Aala

Antimicrobial effects of allicin and ketoconazole on trichophyton rubrum under in vitro condition

Dermatophytosis is caused by a group of pathogenic fungi namely, dermatophytes, is among the most prevalent infectious diseases worldwide. Azole drugs are widely used in the treatment of dermatomycosis, but can cause various side effects and drug resistance to the patients. Hence, for solving this problem can be used from the plant extract as alternative for chemical drugs. Allicin is a pure bioactive compound isolated from garlic was tested for its potential as a treatment of dermatomycosis in this study. This study evaluated the in vitro efficacy of pure allicin against ten isolates of Trichophyton rubrum and the MIC50 and MIC90 ranged from 0.78-12.5 μg/ml for allicin. The results revealed that the order of efficacy based on the MICs values, all isolates showed almost comparable response to allicin and ketoconazole except for some isolates, at 28 °C for both 7 and 10 days incubation. Mann-Whitney test indicate that MICs at 7 days incubation was not observed a significant difference between the effects of allicin and ketoconazole (p > 0.05), but MICs at 10 days incubation, a significant difference was observed (p ≤ 0.05). On the other side, time kill studies revealed that allicin used its fungicidal activity within 12-24 h of management in vitro as well as ketoconazole. In conclusion, allicin showed very good potential as an antifungal compound against mycoses-causing dermatophytes, almost the same as the synthetic drug ketoconazole. Therefore, this antifungal agent appears to be effective, safe and suitable alternative for the treatment of dermatomycosis.

Effects of Pistacia atlantica subsp. kurdica on Growth and Aflatoxin Production by Aspergillus parasiticus

Background Aflatoxins are highly toxic secondary metabolites mainly produced by Aspergillus parasiticus. This species can contaminate a wide range of agricultural commodities, including cereals, peanuts, and crops in the field. In recent years, research on medicinal herbs, such as Pistacia atlantica subsp. kurdica, have led to reduced microbial growth, and these herbs also have a particular effect on the production of aflatoxins as carcinogenic compounds. Objectives In this study, we to examine P. atlantica subsp. kurdica as a natural compound used to inhibit the growth of A. parasiticus and to act as an anti-mycotoxin. Materials and Methods In vitro antifungal susceptibility testing of P. atlantica subsp. kurdica for A. parasiticus was performed according to CLSI document M38-A2. The rate of aflatoxin production was determined using the HPLC technique after exposure to different concentrations (62.5 - 125 mg/mL) of the gum. The changes in expression levels of the aflR gene were analyzed with a quantitative real-time PCR assay. Results The results showed that P. atlantica subsp. kurdica can inhibit A. parasiticus growth at a concentration of 125 mg/mL. HPLC results revealed a significant decrease in aflatoxin production with 125 mg/mL of P. atlantica subsp. kurdica, and AFL-B1 production was entirely inhibited. Based on quantitative real-time PCR results, the rate of aflR gene expression was significantly decreased after treatment with P. atlantica subsp. kurdica. Conclusions Pistacia atlantica subsp. kurdica has anti-toxic properties in addition to an inhibitory effect on A. parasiticus growth, and is able to decrease aflatoxin production effectively in a dose-dependent manner. Therefore, this herbal extract maybe considered a potential anti-mycotoxin agent in medicine or industrial agriculture.

Antifungal Susceptibility Patterns of Candida Species Recovered from Endotracheal Tube in an Intensive Care Unit

Aims. Biofilms formed by Candida species which associated with drastically enhanced resistance against most antimicrobial agents. The aim of this study was to identify and determine the antifungal susceptibility pattern of Candida species isolated from endotracheal tubes from ICU patients. Methods. One hundred forty ICU patients with tracheal tubes who were intubated and mechanically ventilated were surveyed for endotracheal tube biofilms. Samples were processed for quantitative microbial culture. Yeast isolates were identified to the species level based on morphological characteristics and their identity was confirmed by PCR-RFLP. Antifungal susceptibility testing was determined according to CLSI document (M27-A3). Results. Ninety-five strains of Candida were obtained from endotracheal tubes of which C. albicans (n = 34; 35.7%) was the most frequently isolated species followed by other species which included C. glabrata (n = 24; 25.2%), C. parapsilosis (n = 16; 16.8%), C. tropicalis (n = 12; 12.6%), and C. krusei (n = 9; 9.4%). The resulting MIC90 for all Candida species were in increasing order as follows: caspofungin (0.5 μg/mL); amphotericin B (2 μg/mL); voriconazole (8.8 μg/mL); itraconazole (16 μg/mL); and fluconazole (64 μg/mL). Conclusion. Candida species recovered from endotracheal tube are the most susceptible to caspofungin.

Conventional and molecular characterization of Trichophyton rubrum

Different studies illustrated that Trichophyton rubrum, among all species of Trichophyton, is the most prevalent and consequently the most important genus. T. rubrum as a worldwide filamentous pathogen fungus can infect human keratinized tissue (skin, nails and rarely hair), and causes dermatophytosis. Researchers use two general methods for the identification of dermatophytes namely, conventional methods on the basis of phenotype variations and molecular methods on the basis of molecular differences. Due to some limitations in traditional methods, in the recent years, molecular biological methods are regarded as useful in the exact and rapid recognition of dermatophytes. The present study identified nine clinical isolates and one ATCC as a control strain of T. rubrum by using both conventional and molecular methods. The molecular systematics method was used to elucidate genetic diversity among strains of T. rubrum and within Trichophyton species. Morphological characteristics of all colonies T. rubrum quite varies among each other; we revealed that that conventional methods are generally prolonged and may be indecisive. However, molecular studies based on internal transcribed spacer (ITS) sequencing provides a very accurate result, which is more than 96% the similarity of T. rubrum among all isolates, and more than 90% similarity within Trichophyton spp.

Coexistence of aspergilloma and pulmonary hydatid cyst in an immunocompetent individual

Echinococcosis is a zoonotic disease caused by Echinococcus granulosus sensu lato. The liver and lungs are the most commonly sites of infections, but involvements of other organs were also observed. Recently, the coinfection of pulmonary hydatid cyst with aspergilloma has been reported in the literature. Herein, we report a successful treatment of coinfection of cystic echinoccosis with aspergilloma due to Aspergillus flavus in a 34-year-old female. In vitro antifungal susceptibility tests revealed that the MIC values for antifungals employed in this case were posaconazole (0.031μg/ml), itraconazole (0.125μg/ml), voriconazole (0.25μg/ml), and amphotericin B (1μg/ml). The minimum effective concentration for caspofungin was 0.008μg/ml. This coexistence of active pulmonary echinococcosis and aspergillosis is being reported because of its rarity and clinical importance for its management.

Morphological changes and induction of antifungal resistance in Aspergillus fumigatus due to different CO2 levels

Background and Purpose: Aspergillosis is one of the most common opportunistic fungal infections in immunocompromised and neutropenic patients. Aspergillus fumigatus (A. fumigatus) is the most common causative agent of this infection. Due to variable CO2 concentrations that pathogens are exposed to during the infection process and to understand the role of CO2, we examined the effects of various CO2 concentrations as one of the environmental factors on morphological changes and induction of antifungal resistance in A. fumigatus. Materials and Methods: A. fumigatus strains were cultured and incubated under 1%, 3%, 5%, and 12% CO2 atmospheres, each time for one, two, and four weeks. The control culture was maintained for one week without CO2 atmosphere. Morphological changes were investigated and antifungal susceptibility test was performed according to the recommendations of the Clinical and Laboratory Standards Institute (CLSI) M38-A2 document. The results of different CO2 atmospheres were compared with that of the control sample. Results: We found that 1%, 3%, 5%, and 12% CO2 atmospheres were associated with morphological colony changes. Macroscopically, the colonies were shallow dark green, smooth, crisp to powdery with reduced growth; microscopic examination revealed the absence of conidiation. The induction of antifungal resistance in the susceptible strains to itraconazole, voriconazole, and amphotericin B increased after exposure to 12% CO2 atmosphere and four weeks of incubation. The MIC values for itraconazole, voriconazole, and amphotericin B were 16 g/ml, 1 g/ml, and 16 g/ml, respectively. These values for the control group were 0.125 g/ml, 0.125 g/ml, and 2 g/ml, respectively. Conclusion: Exposure to different CO2 atmospheres induced morphological changes in A. fumigatus, it seems to increase the MIC values, as well. In parallel, resistance to both itraconazole and voriconazole was also observed.

Pseudohyphae formation in Candida glabrata due to CO2 exposure

Background and Purpose: Formation of pseudohyphae is considered a virulence factor in Candida species. Generally, Candida glabrata grows as budding yeast cells; however, reports illustrated that C. glabrata could form pseudohyphal cells in response to some stimuli. In this study, we provided insight into the ability of C. glabrata in forming pseudohyphal cells under different levels of carbon dioxide (CO2). Materials and Methods: Candida glabrata reference strain (ATCC 90030) was used in this study. Yeast samples were cultured on Sabouraud dextrose broth (SDB) medium and incubated under 3%, 5%, and 10% CO2 levels for 24, 48 and 72 h. Control cultures were prepared without CO2 pressure for three days. The possibility of pseudohyphae and mycelium formation in C. glabrata was investigated. Results: The results of this study revealed that the most branching filament-like cells were obtained at high CO2 pressure (10%) after 72 h. After three days of low CO2 pressure (3%), only yeast and budding cells were observed without any pseudohyphae formation. Conclusion: CO2 could act as a stimulus and induced formation of pseudohyphae in Candida glabrata yeast cells.