Current Medical Mycology最新文献

Background and purpose: For these intents, proteases cardiovascular disease is the primary cause of death; hence, accurate diagnosis and treatment are urgently required are regarded as prospective agents . High substrate specificity is needed for an effective enzyme, which makes Aspergillus micromycetes, known for producing proteases with precise action, biotechnologically promising. This study mainly aimed to look at the possibilities of Aspergillus species, which had never been mentioned in terms of general proteolytics.

Materials and methods: Every species was cultivated in two-stage submerged conditions with two different nitrogen sources; whereupon, proteolytic activity in culture fluid was determined. Chromogenic peptide substrates and fibrin plates were used to evaluate the thrombin, plasmin, factor Xa, urokinase, protein C-like, activating activities towards hemostasis proteins, as well as fibrinolytic and plasminogen-activating activities of these species.

Results: It was found that A. aureolatus and A. tennesseensis are active proteolytics exhibiting plasmin-like activities (116.17 and 87.09 U×10^-3, respectively), factor Xa-like activity (76.27 and 77.92 U×10^-3, respectively) and urokinase activity (85.99 and 59.91 U×10^-3, respectively). The thrombin-like activity was found for A. tabacinus (50.37 U×10^-3), and protein C-like activity was noticeable for A. creber, A. jensenii, A. protuberus, and A. ruber (62.90, 65.51, 73.37, and 111.85 U×10^-3, respectively). Additionally, more than half of species had the ability to directly activate plasminogen or operate as fibrinolytics.

Conclusion: New proteolytic strains were discovered, offering hope for the therapy of cardiovascular disorders. The high specificity and activity of fungal enzymes make them useful in a variety of fields, including medicine and diagnostics.

Background and purpose: Cerebral aspergillosis is a notorious disease that causes rapid clinical deterioration and carries a poor prognosis. Therefore, it requires timely diagnosis and prompt management.

Case report: This study reports a case of fungal cerebral abscess in a 26years old man following hemodialysis,2 months afterdengue-induced acute kidney disease. Aspergillus fumigatus was recovered from a brain abscess specimen that was subjected to a parietal craniotomy. The patient was successfully treated with oral Voriconazole 400mg BD for 2 days, followed by 200 mg BD for 3months.

Conclusion: Hemodialysis patients are at high risk offungal infections due to the frequent use of catheters or the insertion of needles to access the bloodstream. Therefore, a high index of suspicion of fungal infection is required in patients with hemodialysis by the clinician for early diagnosis and treatment.

Background and purpose: Given the high mortality rate of invasive candidiasis in hospitalized pediatric patients, it is crucial to establish a predictive system to achieve early diagnosis and treatment of patients who are likely to benefit from early antifungal treatment. This study aimed to assess the Candida colonization index, species distribution, and antifungal susceptibility pattern of Candida strains isolated from pediatric patients with high Candida colonization index (CI).

Materials and methods: This study was carried out at the Children's Medical Center in Tehran-Iran. In total, 661 samples were collected from 83 patients. The Candida CI was calculated according to the descriptions of previous studies. The isolates were identified using polymerase chain reaction-based techniques. The Clinical and Laboratory Standard Institute protocol M60 was used to conduct the antifungal susceptibility test.

Results: A colonization index greater than 0.5 was confirmed in 29 cases (58% of positive samples) with two children developing candidemia. Candida albicans (n=53, 49.5%) was the most common Candida species in patients with CI > 0.5. Except for acute lymphoblastic leukemia, no risk factors were linked to a high index in colonized children (P > 0.05). Twelve isolates (7.01%) were multi-azole resistant with high MICs against both isavuconazole and ravuconazole and seven strains (4.09%) were echinocandins resistant.

Conclusion: In pediatric intensive care units, patients are at risk of fungal infection, particularly candidemia. In this study, more than half of the children with positive yeast cultures had CI > 0.5, and 6.8% developed candidemia.

Background and purpose: Scedosporium species are ubiquitous environmental fungi, which are considered emerging agents that trigger disease in humans and animals. The present study aimed to determine Scedosporium dehoogii strain isolated from paddy field soil samples using semi-selective media and evaluate its antifungal susceptibility profile.

Materials and methods: Three paddy field soil samples were collected during an investigation for the isolation of Scedosporium species in Mazandaran province, Iran. Morphological and molecular analyses based on ITS-rDNA sequencing were performed. Furthermore, in vitro antifungal susceptibility testing for conventional drugs and novel imidazole (luliconazole) was performed based on Clinical and Laboratory Standards Institute M38-A3 guidelines.

Results: In this study, S. dehoogii was isolated from the soil in paddy fields. Based on the results, itraconazole and luliconazole showed the least and most antifungal activity against this isolate, respectively.

Conclusion: Based on the findings, molecular identification was essential for distinguishing the species of S. dehoogii. Remarkably, luliconazole showed potent activity against this strain.

Background and purpose: Fungal infection by species of pathogenic Candida with antifungal resistance is currently a serious problem. Treatment with new medications is becoming more challenging to manage this type of infection. The present study aimed to investigate the antifungal effect of essential oils (EOs) against itraconazole-resistant species of pathogenic Candida.

Materials and methods: Seven essential oils were tested on 15 clinical isolates of itraconazole-resistant Candida from patients with vulvovaginal candidiasis. The antifungal action of selected EOs was evaluated using the disc diffusion method with the determination of the minimum inhibitory concentration (MIC) of effective Eos.

Results: Radish EO was the most effective type against all Candida isolates with MICs between 3.125% and 6.25% (v/v) .It also had a stronger effect than itraconazole. Six other EOs showed antifungal effects at varying concentrations and were dependent upon the type of isolate. Low concentrations of these six EOs were more effective against many isolates than their high concentrations. Moreover, camphor and linseed EOs were less effective on isolates.

Conclusion: Radish EO has a strong antifungal activity against itraconazole-resistance species of Candida, even more than itraconazole. The antifungal action of some EOs can be increased through the use of low concentrations.

Background and purpose: Trichophyton quinckeanum, a known zoophilic dermatophyte responsible for favus form in rodents and camels, is occasionally reported to cause human infections.

Case report: This study aimed to report a case of tinea corporis caused by T. quinckeanum that experienced annular erythematous pruritic plaque with abundant purulent secretions. In June 2021, a 15-year-old girl with an erythematous cup shape lesion on the right wrist bigger than 3 cm in diameter was examined for tinea corporis. Since March, 2016 her family has kept several camels at home. Direct examination of skin scraping and purulent exudates revealed branching septal hyaline hyphae and arthrospore. Morphological evaluation of the recovered isolate from the culture and sequencing of ITS1-5.8S rDNA-ITS2 region resulted in the identification of T. quinckeanum. Antifungal susceptibility testing showed that this isolate had low minimum inhibitory concentration (MIC) values for luliconazole, terbinafine, and tolnaftate, but high MICs to itraconazole, fluconazole, posaconazole, miconazole, isavuconazole, ketoconazole, clotrimazole, and griseofulvin. However, the patient was successfully treated with oral terbinafine and topical ketoconazole.

Conclusion: It can be said that T. quinckeanum is often missed or misidentified due to its morphological similarity to T. mentagrophytes/T. interdigitale or other similar species. This dermatophyte species is first reported as the cause of tinea corporis in Iran. As expected, a few months after our study, T. quinckeanum was detected in other areas of Iran, in a few cases.

Background and purpose: The hospital environment was reported as a real habitat for different microorganisms, especially mold fungi. On the other hand, these opportunistic fungi were considered hospital-acquired mold infections in patients with weak immune status. Therefore, this multi-center study aimed to evaluate 23 hospitals in 18 provinces of Iran for fungal contamination sources.

Materials and methods: In total, 43 opened Petri plates and 213 surface samples were collected throughout different wards of 23 hospitals. All collected samples were inoculated into Sabouraud Dextrose Agar containing Chloramphenicol (SC), and the plates were then incubated at 27-30ºC for 7-14 days.

Results: A total of 210 fungal colonies from equipment (162, 77.1%) and air (48, 22.9%) were identified. The most predominant isolated genus was Aspergillus (47.5%), followed by Rhizopus (14.2%), Mucor (11.7%), and Cladosporium (9.2%). Aspergillus (39.5%), Cladosporium (16.6%), as well as Penicillium and Sterile hyphae (10.4% each), were the most isolates from the air samples. Moreover, intensive care units (38.5%) and operating rooms (21.9%) had the highest number of isolated fungal colonies. Out of 256 collected samples from equipment and air, 163 (63.7%) were positive for fungal growth. The rate of fungal contamination in instrument and air samples was 128/213 (60.1%) and 35/43 (81.2%), respectively. Among the isolated species of Aspergillus, A. flavus complex (38/96, 39.6%), A. niger complex (31/96, 32.3%), and A. fumigatus complex (15/96, 15.6%) were the commonest species.

Conclusion: According to our findings, in addition to air, equipment and instrument should be considered among the significant sources of fungal contamination in the indoor environment of hospitals.

Background and purpose: Genotyping of pathogenic microorganisms is important for epidemiological studies and the adoption of appropriate strategies to control infectious diseases. In this regard, the present study aimed to genotype Candida albicans strains isolated from vulvovaginal candidiasis (VVC) patients using combined ABC type (25SrDNA) and repetitive sequence (RPS) typing systems. using combined typing systems of ABC type (25SrDNA) and repetitive sequence (RPS).

Materials and methods: In total, 140 patients with VVC were investigated. Vaginal discharges were collected on Sabouraud dextrose agar and identified by CHROMagar. After species identification, a polymerase chain reaction system targeting 25S rDNA as well as ALT repeats in the RPS was designed to determine C. albicans genotypes. The dendrogram was constructed by zero-one matrix data based on the combination of ABC and RPS typing systems. Statistical analysis of data was performed in SPSS software (version 23).

Results: In total, 41 (29.3%) Candida isolates were obtained from 140 VVC patients. The most common Candida species that were identified included C. glabrata (56.1%) and C. albicans (39%). Genotype A3 with five isolates (31.25%) had the highest frequency, followed by B2/3 with three isolates (18.3%), A3/4, C3/4, and B3/4 with two isolates (12.5%), and C2/3 and C3 with one isolate (6.25%), respectively. No significant association was found between the genotypes and antifungal resistance (P<0.05).

Conclusion: The results showed that non-albicans Candida species are more prevalent in VVC patients, compared to C. albicans. The results also indicated that ABC and RPS typings are useful for rapid genotyping and differentiation of C. albicans isolates in regional and small-scale studies.

Background and purpose: Candidemia is a major cause of morbidity and mortality among patients receiving immunosuppressive therapy and those hospitalized with serious underlying diseases. Here, we investigated the epidemiological, clinical, and mycological features of candidemia in Tehran, Iran.

Materials and methods: A prospective observational study of all patients diagnosed with candidemia was performed at two referral teaching hospitals in Tehran, Iran, from February to December 2018. Demographic characteristics, underlying diseases, risk factors, clinical symptoms, and laboratory analyses of candidemic patients with positive culture were mined. Candida isolates were molecularly identified by sequencing of the internal transcribed spacer region (ITS1-5.8S-ITS2). The antifungal susceptibility testing for fluconazole, itraconazole, voriconazole, posaconazole, amphotericin B, caspofungin, micafungin, and anidulafungin against the isolates was performed using CLSI broth microdilution reference method (M27-A3).

Results: A total of 89 episodes were identified, with an incidence of 2.1 episodes/1000 admissions. The common underling disease were malignancy (46%), renal failure/dialysis (44%), and hypertension (40%). The overall crude mortality was 47%. C. albicans (44%) was the most frequent causative agent, followed by C. glabrata (21%), C. parapsilosis complex (15%), C. tropicalis (11%), and C. lusitaniae (3.5%). All the isolates were susceptible to amphotericin B. The activity of all four azoles was low against non-albicans Candida species, especially C. tropicalis.

Conclusion: The increase in non-albicans Candida species with reduced susceptibility to antifungal drugs might be alarming in high-risk patients. Therefore, accurate knowledge of predisposing factors and epidemiological patterns in candidemia are effective steps for managing and decreasing the mortality rate in candidemia.

Background and purpose: The human mouth mucosal surface is colonized by indigenous microflora, which normally maintains an ecological balance among different species. However, certain environmental or biological factors may disrupt this balance, leading to microbial diseases. Candida albicans biofilms are formed on indwelling medical devices and have an association with both oral and invasive candidiasis. This study aimed to compare the amount of adherent C. albicans and the biofilm formed on different denture base materials. The adhesion of C. albicans to denture base materials is widely recognized as the main reason for the development of denture stomatitis.

Materials and methods: In total, 56 polymethyl methacrylate (PMMA) acrylic resin disc-shaped samples were divided into four groups as follows: 1) chemically polymerized PMMA, 2) heat-polymerized PMMA, 3) computer-aided design and computer-aided manufacturing (CAD/CAM) PMMA in high polish, and 4) CAD/CAM resins in glazed form. The adherent cells and formation of C. albicans strains (562, 1905, 1912, and 1949) biofilm were measured by the 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) method and use of a microplate reader. Moreover, morphological alterations of C. albicans cells were investigated using scanning electron microscopy (SEM).

Results: The biofilm formation was significantly lower on CAD/CAM acrylic resins, compared to conventional denture base materials. The obtained results were confirmed by the SEM images of C. albicans biofilms. CAD/CAM PMMA-based polymers may be preferable to inhibit C. albicans biofilm formation and reduce Candida-associated denture stomatitis in long-term use.

Conclusion: Based on the findings, the CAD/CAM technique can be used as an efficient technique for denture fabrication as it inhibits microbial accumulation, and consequently, microbial biofilm.