Current Medical Mycology最新文献

Background and purpose: The COVID-19 pandemic may be an aggravating risk factor for the delay of the diagnoses of serious illnesses, such as oral squamous cell carcinoma, as well as poor management of patients with underlying morbidities, the onset of oral lesions, and antifungal susceptibility to opportunistic fungal infections. Oral candidiasis is one of the most common oral features of COVID-19.

Case report: This study aimed to report an 83-year-old female diagnosed with oral carcinoma who developed oropharyngeal candidiasis after falling ill with COVID-19. In late 2020, this patient was hospitalized for COVID-19 pneumonia. A fissured tongue with white scars appeared after the COVID-19 recovery that caused pain, dysphasia, and dysarthria. The sequencing result based on the internal transcribed spacer rDNA region confirmed Candida glabrata. Its antifungal susceptibility showed susceptibility to nystatin, fluconazole, and caspofungin, but resistance to the other azoles and amphotericin B.

Conclusion: Risk of fungal infections, such as Candida seems to be high in patients with severe COVID-19, mainly affecting the oral mucosa. However, whether they are directly attributed to COVID-19 or other surrounding factors is unknown.

Background and purpose: The current study aimed to report a multiplex polymerase chain reaction (PCR) assay as a monitoring technique to differentiate aflatoxigenic from non-aflatoxigenic strains of Aspergillus flavus isolated from pistachio orchards soil.

Materials and methods: In total, 25 A. flavus strains were isolated from soil samples of pistachio orchards. To test the strains for Aflatoxin B₁ (AFB₁)-producing ability, thin-layer chromatography (TLC) was used and the amounts of AFB₁ were measured by high-performance liquid chromatography (HPLC). Multiplex PCR was used as a genome-based method to detect genes responsible for AFB₁ production by A. flavus and the results were analyzed in terms of speed and specificity of detection. A set of four primers was designed specifically for the omtA, omtB, ver-1, and aflR genes which are commonly present in aflatoxin biosynthetic pathways.

Results: The AFB₁ production by the A. flavus strains ranged from 0 to 321 ρg/μl. Four-band patterns of the primer sets were observed only in AFB₁-producing A. flavus strains. Moreover, 18 out of the 25 strains showed all four bands belonging to omtA, omtB, ver-1, and aflR, whereas 7 strains did not display omtA, or aflR-related bands, in non-toxigenic and low toxin-producing A. flavus.

Conclusion: The multiplex PCR is a supplementary strategy to current conventional mycotoxin analytical techniques, such as TLC and HPLC. It could be used as an efficient method to differentiate aflatoxigenic from non-aflatoxigenic strains of A. flavus. This achievement is crucial to minimize fungal contamination of food, feed, and agricultural commodities, thereby reducing the risk of subsequent aflatoxin consumption.

Background and purpose: Regarding the wide-spectrum antimicrobial effects of curcumin and silver, this study aimed to evaluate the antifungal activity of green-synthesized curcumin-coated silver nanoparticles (Cur-Ag NPs) against a set of Candida and Aspergillus species.

Materials and methods: Cur-Ag NPs were synthesized by mixing 200 µL of curcumin solution (40 mM) and 15 mL of deionized water. The mixture was stirred for 3-5 min, followed by the addition of 2.5 mL of silver nitrate solution (2.5 mM). The resulting solution was incubated for 3 days. Antifungal susceptibility of 30 fungal isolates of Aspergillus and Candida to fluconazole and itraconazole, as well as the activity of Cur-Ag NPs against the isolates, were determined, both alone and in combination, using broth microdilution according to the Clinical and Laboratory Standards Institute guidelines.

Results: Cur-Ag NPs demonstrated promising antifungal activity, particularly against Candida species. The geometric mean value of the minimum inhibitory concentration of Cur-Ag NPs was significantly lower than that of fluconazole for all the studied fungi. Similarly, it was lower than those of itraconazole in C. albicans and A. fumigatus. The minimum fungicidal concentrations of Cur-Ag NPs were markedly better than those of fluconazole but still inferior to those of itraconazole.

Conclusion: Cur-Ag NPs demonstrated indisputable antifungal activity and great potential that can be harnessed to combat fungal infections, particularly those caused by azole-resistant strains of Aspergillus and Candida.

Background and purpose: Candida auris is a multidrug-resistant yeast that rapidly spreads, making it the leading Candidate for the next pandemic. One main leading cause of emerging resistant C. auris isolates is nonsynonymous mutations. This study aimed to detect the Y132F mutation, one of the most important azole resistance-associated mutations in the ERG-11 gene of C. auris, by developing a reliable high-resolution melt (HRM)-based method.

Materials and methods: Five C. auris isolates from Iran, plus three control isolates from other Clades were used in the study. The antifungal susceptibility testing through micro broth dilution was performed to recheck their susceptibility to three azole antifungals, including fluconazole, itraconazole, and voriconazole. Moreover, the polymerase chain reaction (PCR) sequencing of the ERG-11 gene was performed. Following the bioinformatic analysis and HRM-specific primer design, an HRM-based assay was developed and evaluated to detect ERG-11 mutations.

Results: The minimum inhibitory concentrations of fluconazole among Iranian C. auris isolates ranged from 8 to 64 μg/mL. The PCR-sequencing of the ERG-11 gene and bioinformatic analyses revealed the mutation of Y132F, a substitution consequence of A to T on codon 395 in one fluconazole-resistant isolate (IFRC4050). The developed HRM assay successfully differentiated the targeted single nucleotide polymorphism between mutant and wild types (temperature [Tm]: 81.79 ℃ - cycle threshold [CT]: 20.06 for suspected isolate). For both mutant and non-mutant isolates, the mean Tm range was 81.79-82.39 °C and the mean CT value was 20.06-22.93. These results were completely in accordance with the findings of DNA sequencing.

Conclusion: The fast-track HRM-based method successfully detected one of the most common mechanisms of resistance in the ERG-11 gene of C. auris within 3 h. Finally, the development of more panels of HRM assays for the detection of all azole resistance mutations in C. auris ERG-11 is recommended to expand the scope of the field and facilitate the elaboration of rapid and accurate methods of antifungal resistance assessment.

Background and purpose: Invasive fungal disease (IFD) is a common and serious consequence of leukemia in children and the incidence of these infections has increased due to chemotherapy. This study aimed to present the epidemiology of IFD in a cohort of children with leukemia from a tertiary reference institution in Oman.

Materials and methods: A retrospective study of IFDs in pediatric patients below 13 years of age with newly diagnosed or relapsed leukemia was conducted at the Royal Hospital in Muscat, Oman. From 2010 to 2017, IFD episodes in children with leukemia were evaluated retrospectively, considering age, gender, type of leukemia, chemotherapy regimen, IFD detection phase, neutropenia, prevention, diagnostic method, and treatment.

Results: Between 2010 and 2017, 198 children with leukemia were admitted and treated at Royal Hospital. Invasive fungal infection (IFI) was diagnosed in 32 patients out of 198 (16.1%), and IFI was defined as probable and proven in 53% (n=17) and 47% (n=15) of the cases, respectively. At 1.1:1, the male-to-female ratio was roughly equal. According to chest computed tomography scans, 65.6% of patients had radiological features of fungal infections. Positive fungal cultures were found in the bronchoalveolar lavage of three patients, 37.5% of whom had positive blood cultures, and 3% had positive urine cultures as a neonatal invasive candidiasis. In three patients, invasive aspergillosis caused pulmonary IFD, accounting for 9.3% of all infection sites. Candidaemia was found in 28% of IFD patients, and the most common organism was Candida tropicalis (15.6%), followed by Candida parapsilosis (6.25%). Furthermore, the major risk factor was febrile neutropenia.

Conclusion: In children with leukemia, invasive fungal infection is common and serious. Despite aggressive treatment, mortality among these high-risk patients remains high.

Background and purpose: Onychomycosis caused by dematiaceous fungi is rarely reported and the identification is also quite tricky due to poor sporulation. Recent emergence of dematiaceous fungi as a major cause of onychomycosis is a matter of concern in the field of mycology. Therefore, this study aimed to understand the dematiaceous fungi as a possible cause of onychomycosis, especially among agricultural workers. In addition, the evaluation of the antifungal susceptibility patterns led to the idea of an accurate drug that will help to treat and prevent antifungal resistance.

Materials and methods: The standard procedure was followed for direct microscopic examination and fungi isolation. Furthermore, antifungal susceptibility testing was conducted in accordance with the Clinical and Laboratory Standards Institute M-38-A2 protocol.

Results: Both potassium hydroxide and fungal positivity were found in 275 out of 356 suspected cases, 52%, 4.3%, 28.7%, and 14.9% of which were non-dermatophytic molds (NDMs), yeast, dermatophytes, and sterile hyphae, respectively. Among NDMs (52%, n=143), 45.5% (n=65) were hyaline hyphomycetes and 54.5% (n=78) were dematiaceous hyphomycetes. Among dematiaceous fungi, Pestalotiopsis spp. and Arthrinium spp. were the commonly isolated ones. Additionally, azoles, amphotericin-B, and anidulafungin showed excellent antifungal activity against tested isolates.

Conclusion: Dematiaceous fungi are now becoming a potential cause of onychomycosis. A more detailed study is needed on the identification of these emerging isolates and the mode of action of antifungal drugs for a better treatment strategy.

Background and purpose: Invasive fungal infections caused by Cyberlindnera fabianii (Cy. fabianii) have recently increased despite the low virulence potential of this yeast. However, limited information about the widely-used commercial biochemical identification systems has led to an underestimation of Cy. fabianii infections in clinical settings.

Case report: This study reports a case of prosthetic joint infection in a patient who had a previous history of total knee replacement surgery. Cy. fabianii was recovered from intraoperative culture specimens identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and confirmed using molecular assays. It was, however, initially misidentified as Candida utilis by phenotypic identification.

Conclusion: Due to the emergence of uncommon yeast species, it is important to accurately identify and perform antifungal susceptibility testing on uncommon yeast isolates for appropriate management.

Background and purpose: India witnessed an explosive rise in mucormycosis following COVID-19 infection. Pulmonary mucormycosis closely followed rhino orbital mucormycosis as the most common presentation. The need for advanced resources and lack of clinical suspicion for COVID-19-associated pulmonary mucormycosis led to widespread underdiagnosis and poor response to late therapy. The present study aimed to assess the prevalence of pulmonary mucormycosis in COVID-19-associated rhino-orbital mucormycosis using non-invasive techniques, such as sputum microscopy and chest imaging.

Materials and methods: A prospective observational study was conducted at the Institute of Internal Medicine, Rajiv Gandhi Government General Hospital in Chennai, India between June 2021 and July 2021. All hospitalized patients with proven rhino orbital mucormycosis with or without cerebral involvement within three months of confirmed COVID-19 infection who had clinical symptoms compatible with pulmonary mucormycosis were included in this study. These patients were screened for probable and possible COVID-19-associated pulmonary mucormycosis using computed tomography (CT) chest imaging and sputum microscopy within 48 h of hospital admission.

Results: Based on the findings, 8 (16%) out of 50 patients with rhino-orbital mucormycosis, had associated possible or probable pulmonary mucormycosis. All 8 patients were diabetics and had characteristic CT chest findings while only half of them had positive sputum microscopy. A higher prevalence of probably disseminated COVID-19-associated mucormycosis was noted among 51-60-year-old males with the use of corticosteroids and oxygen for COVID-19 therapy. The mortality rate was 100% in probably disseminated mucormycosis, 50% in possible disseminated mucormycosis, and only 9.5% in isolated rhino-orbital mucormycosis.

Conclusion: Non-invasive and feasible methods, such as sputum microscopy and chest imaging can be considered for early screening and intensive management of probably disseminated mucormycosis to improve prognosis.

Background and purpose: Considering the possible role of fungal sensitization in the treatment of resistant asthma, which may lead to the remodeling of bronchial structure, we theorized that itraconazole could result in better control of asthma. In this regard, this study aimed to compare the effects of itraconazole and prednisolone (routinely prescribed) on clinical, structural, and biomarker findings of the remodeling of asthma.

Materials and methods: This double-blind controlled randomized clinical trial was performed on 70 adult patients suffering from severe persistent asthma. The intervention group received 200 mg of itraconazole per day, and the control group received 10 mg of prednisolone per day, for 32 weeks, in addition to the classic treatment of asthma. The subjects were randomly divided into two groups, and assigned by sealed envelope. Blinding was performed by repacking the drug in a similar container. Primary outcomes were asthma control test score, fibroblast growth factor 2, and wall area percentage on RB1 bronchus measured by computed tomography. The outcomes were compared in subjects classified as allergic, eosinophilic, T2 low asthma, and four types of inflammatory cell classification in sputum.

Results: Seventy subjects finished the 32-week trial (35 subjects in each group). Baseline data did not show significant differences between groups. A comparison of asthma variants showed significantly more severe cough and dyspnea in the allergic variant and higher spirometry results in T2-low asthma. Sputum cytology revealed a mixed pattern as the most frequent type (47%). After the trial, two groups improved in many parameters; however, FGF-2 improved more significantly by itraconazole (4.66±16.92 decreased to 1.14±2.98), and FEV1/FVC was significantly higher in the itraconazole group, compared to the control group. These results did not change in terms of asthma variants and sputum classification.

Conclusion: Itraconazole was superior to prednisolone in the treatment of many clinical and spirometry aspects in severe persistent asthma.

Background and purpose: The increasing rate of opportunistic infections caused by Candida and other yeasts is becoming a major health concern worldwide. However, systematic data on the epidemiology and the yeast species infections in Malaysia is still limited. In this regard, the present research aimed to identify pathogenic yeasts utilizing an economically practical and easily available molecular technique and evaluate the prevalence of pathogenic yeasts in a Malaysian tertiary care hospital.

Materials and methods: Yeast isolates were collected from Sultan Abdul Halim Hospital, Kedah, Malaysia, from October 2020 to October 2021. Molecular identification of the isolates was performed by one enzyme-based polymerase chain reaction-restriction fragment length polymorphism method.

Results: Candida albicans was the most prevalent species, accounting for 120 isolates (59%) in total. The most prevalent non-albicans Candida species were C. tropicalis (n=33, 16%), C. krusei (Pichia kudriavzevii) (n=12, 5.8%), C. glabrata (n=12, 5.8%), and C. parapsilosis (n=6, 3%). Other unusual Candida species were C. guilliermondii (2), C. metapsilosis (2), C. orthopsilosis (1), C. lusitaniae (1), C. rugosa (1), C. haemulonii (1), C. bracarensis (1), and C. dubliniensis (1). Moreover, Talaromyces marneffei (1), Kodamaea ohmeri (1), Cryptococcus neoformans (3), and Cryptococcus laurentii (1) were among the other yeasts identified.

Conclusion: The Molecular technique used in this study identified 96% of isolates, including mixed species. According to the findings, the most prevalent species are C. albicans, C. tropicalis, C. krusei, and C. glabrata.