Current Medical Mycology

Clinical, epidemiological, and mycological features of patients with candidemia: Experience in two tertiary referral centers in Iran

Mohammad Kord — 2022-11-20

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 anidulafunginagainst 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.

Evaluation of Candida albicans biofilm formation on conventional and computer-aided-design/computer-aided manufacturing (CAD/CAM) denture base materials

Milad Larijani — 2022-11-20

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.

Epidemiology and molecular identification of mixed yeast isolates in Malaysia: A way forward

Humaira Farooq — 2022-11-20

Background and Purpose: Invasive candidiasis is one of the most common systemic mycoses, and studies have shown mixed yeast infections. Malaysia lacks mixed yeast culture data.

Materials and Methods: Yeast isolates were collected in Sultan Abdul Halim Hospital, North Malaysia, from October 2020 to October 2021. Chromogenic Candida differential agar media and PCR-RFLP were used to identify yeast species.

Results: A total of 206 yeast isolates were collected from different body sites of patients. The majority of the yeast isolates (n=104) were obtained from the urine. Other isolates were extracted from blood (n=52), vaginal swabs (n=45), ear discharge (n=2), tracheal aspirate (n=2), tissue (n=2), skin (n=1), nail (n=1), sputum (n=1), and cerebrospinal fluid (n=1). In total, 200 yeast samples were identified as single species, and six isolates were a mixture of Candida species.

Conclusion: Malaysia lacks accurate epidemiological data on mixed yeast infections. We identified all samples to the species level, including mixed yeast cultures, using the MspI enzyme and PCR-RFLP.

Oral Candida colonization and anti-fungal susceptibility pattern in patients with hematological malignancy

Maryam Talebshoushtari Zadeh — 2022-11-20

Background and Purpose: Candidiasis is regarded as one of the most important fungal infections and a cause of disease and mortality in patients with hematological malignancy. Accordingly, antifungal prophylaxis is of significant importance in this regard. This study aimed to identify the epidemiology of Candida colonization and evaluate its antifungal susceptibility pattern in patients with hematological malignancy.

Materials and Methods: In this study, the samples were collected from the oral cavity of 100 patients, and Candida colonization was confirmed by fungal culture. Candida strains were also identified by ITS-PCR. In vitro antifungal susceptibility tests against fluconazole, amphotericin B, and caspofungin were performed according to CLSI M60.

Results: Demographic characteristics, comorbidities, distribution of Candida species (spp.), and antifungal susceptibility were analyzed in this study. The study participants included 100 patients with a mean age of 15.48%±48.74 years (age range: 17-84 years). Regarding gender distribution, the majority (64%) of the patients were male. In terms of the distribution of underlying hematologic malignancy, 27% of the cases had lymphoma. The most commonly isolated species among patients were C. albicans complex (49%; n=49), C. glabrata (39%; n=39), and co-colonization of C. albicans complex and C. with C. glabrata (10%; n=10). The overall resistance of C. albicans complex was 5% to fluconazole (n=5) and 2% to amphotericin B (n=2). Furthermore, C. glabrata showed 11% (n=11) resistance to fluconazole and was susceptible to amphotericin B. All Candida spp. isolated from patients who were susceptible to caspofungin.

Conclusion: The high rate of colonization of Candida spp., especially the significant increase in the frequency of C. glabrata in patients with blood malignancies and the gradual increase in resistance to fluconazole, necessitate a change in the use of antifungal drugs for the prevention and experimental treatment of hematological malignancy.

Candida auris and COVID-19: A health threatening combination

Shaghayegh Khojasteh — 2022-11-20

Since its first emergence in December 2019, due to its fast distribution throughout the world, SARS-COV-2 become a global concern. With the extremely increased number of hospitalized patients, this situation provided a potential basis for the transmission of nosocomial infections. Candida auris is a multidrug-resistant pathogen with improved transmission dynamics and resistance traits. During the worldwide spread of COVID-19, cases or outbreaks of C. auris colonization or infection have been reported. Resistance to antifungal drugs has been observed in the causative agents of the majority of such cases. The focus in this review is on COVID-19-associated C. auris infections (case studies/outbreaks) and the pandemic's potential effect on antifungal drug resistance.

Candida species isolated from clinical samples in a tertiary hospital in Honduras: Where is Candida auris?

Bryan Ortiz — 2022-11-20

Background and Purpose: Infections by emerging and multiresistant Candida species are becoming more frequent throughout the world. This study aimed to describe Candida species in different wards of a tertiary hospital in Honduras.

Materials and Methods: The prevalence of species within the C. albicans complex was estimated using a molecular approach, and C. auris was investigated using a yeast poolbased DNA extraction method. In total, 328 yeast isolates were identified using phenotypic approaches. For the identification of species within the albicans complex, a molecular approach based on the size polymorphisms of the hpw1 gene was used. In addition, a technique was optimized based on DNA extraction in pools for the rapid identification of C. auris.

Results: A total of 11 species of Candida were identified in the hospital wards. C. albicans showed the highest number of isolates (52.4%). Within the C. albicans complex, C. albicans sensu stricto was the most common, followed by C. dubliniensis. However, C. auris was not found.

Conclusion: Reports on the distribution of Candida species in Honduras are limited; accordingly, the data from this study are of importance for a better understanding of their epidemiology. Moreover, a simple method was offered for the detection of C. auris that could help in its detection in low-resource settings.

A rare case of a nasal cavity fungus ball due to Aspergillus niger

Emine Nur Köroğlu — 2022-11-20

Background and Purpose: Fungus Ball (FB) is a non-invasive fungal infection caused mainly by Aspergillus species. It can occur after root canal treatments are applied to the teeth adjacent to the maxillary sinus. These balls are commonly seen in the paranasal sinuses and rarely observed in the nasal cavity. This report attempted in to highlight such a rare case of fungal infection which requires accurate observation. Moreover, it highlights the importance of careful microbiological and histopathological examinations that were combined with imaging and can lead to a definitive diagnosis.

Case report: Herein, we report a rare case of a FB found in the vicinity of the nasal cavity of a 73-year-old male patient. Microbiological examination supported by radiographic and histopathological results indicated that the FB is due to Aspergillus niger. Excised surgery was done to the FB area, and the patient was referred to the postoperation room with the proper recommendations. After the wound healed, the total denture was performed as requested by the patient, and his overall oral health was improved.

Conclusion: In this article, we report the first case of a rare FB in the vicinity of the nasal cavity of a 73-year-old male patient. The appropriate investigation is an essential step in the diagnostic process for these infections and requires effective communication and collaboration.

Epidemiology, species distribution, antifungal susceptibility, and outcome of candidemia in intensive care units in Isfahan, Iran

Azam Haghighatfard — 2022-11-27

Background and Purpose: Candidemia is known as an invasive fungal infection with high mortality. The prevalence of candidemia in intensive care unit (ICU) patients is more than in other hospital wards. Early diagnosis of candidemia in these patients is essential for disease management.

Materials and Methods: This study included 250 patients suspected of candidemia. Blood samples were taken from patients and incubated. The fungal isolates were identified by PCR-RFLP method using MSP I restriction enzyme. Demographic characteristics, risk factors, underlying diseases, and laboratory analysis results were mined in this study.

Results: In total, 22 blood samples were identified as positive for Candida yeasts in culture. The most common underlying diseases in these patients were heart disease and hypertension (36.4%). Candida albicans with 12 cases (54.5%) was the most isolated species, followed by C. parapsilosis (n=5, 22.7%), C. glabrata (n=4, 18.2%), and C. tropicalis (n=1, 4.5%) in descending order. Intravenous catheter use was recognized as the most common risk factor in patients with candidemia (77.3%), and after that, the use of mechanical ventilation (68.2%) and urinary catheter (40.9%) obtained the highest frequency. Furthermore, 17 patients were prescribed at least one antifungal drug, of which fluconazole was the most used (36.4%). The mortality rate in patients in this study was 63.6%. All C. albicans isolates were susceptible to antifungal agents but in non-albicans Candida (NAC), drug resistance to fluconazole, voriconazole, and caspofungin were observed.

Conclusion: Although C. albicans was the most common fungal species in this study, the prevalence of NAC species was high. The increasing frequency of NAC species is a concern because they have different patterns of drug resistance. Recognition of risk factors in patients admitted to ICUs can help prevent candidemia or properly manage the disease.