Current Medical Mycology最新文献

Mucormycosis is an opportunistic, aggressive, and angioinvasive fungal infection associated with a high mortality rate as it disseminates and infects the whole body if not treated early. Most conventional diagnostic methods require time and may also generate false-negative reports due to the several lacunae associated. On the other hand, molecular methods are rapid, reliable, and can be applied to different biological samples, such as fresh tissue, formalin-fixed paraffin-embedded blocks, serum, and urine. Mucorales are angio-invasive, and many studies have found the circulating fungal DNA (a non-invasive form of DNA) in the blood and urine of the patient. In addition, with the increase in the usage of steroid drugs in this COVID scenario, the rate of mucormycosis infection has taken a sudden rise. In light of this situation, there is an imperative need to diagnose these infections at the earliest.

Background and purpose: Disseminated fusariosis is an opportunistic infection caused by the hyaline fungus Fusarium spp. and occurs mainly in patients with leukemia.

Case report: Two cases of disseminated fusariosis in pediatric patients are presented. Profound and prolonged neutropenia, fever, myalgia, and skin lesions in the legs were present in two girls with leukemia undergoing chemotherapy. In the first case, infection by Fusarium spp. was confirmed by anatomopathological findings, pathogen isolation, and polymerase chain reaction. In the second case, Fusarium solani infection was confirmed by mass spectrometry using blood cultures and skin lesion samples.

Conclusion: It is important to consider disseminated fusariosis in high-risk patients who present with profound and prolonged neutropenia and persistent fever that does not resolve after broad-spectrum antibiotics to initiate antifungal therapy in a timely manner.

Background and purpose: Oral candidiasis has become a growing problem in hospitals worldwide, and the development of antifungal drug resistance in Candida species constitutes a serious concern. This study aimed to evaluate the in vitro efficacy of nystatin, and micafungin with chlorhexidine against fluconazole-resistant and fluconazole-sensitive Candida albicans (C. albicans) isolates.

Materials and methods: In this experimental-laboratory study, a total of 20 fluconazole-resistant (n=10) and fluconazole-susceptible (n=10) C. albicans strains were obtained from the reference culture collection of the Invasive Fungi Research Center in Mazandaran University of Medical Sciences, Sari, Iran. In vitro combination of nystatin and micafungin with chlorhexidine was performed using a microdilution checkerboard method based on the Clinical and Laboratory Standards Institute guideline.

Results: Micafungin had the highest antifungal activity against C. albicans susceptible and resistant strains, with a Geometric mean of (GM) =0.008µg/ml and GM=0.008µg/ml, followed by nystatin with GM=0.06µg/ml and GM=0.042µg/ml and chlorhexidine with GM=0.25µg/ml and GM=0.165µg/ml against C. albicans resistant and sensitive strains, respectively. The interaction of micafungin and nystatin with chlorhexidine showed a synergistic interaction against most C. albicans strains. In addition, no antagonistic interaction was observed between micafungin, nystatin, and chlorhexidine against C. albicans strains.

Conclusion: The synergistic interaction of micafungin with chlorhexidine against azole-resistant C. albicans suggests an alternative approach to overcome antifungal drug resistance. However, further studies are needed for in vivo evaluation.

Background and purpose: Candidemia remained important in the intensive care units (ICU) during the COVID-19 pandemic. This study aimed to investigate the clinical and laboratory data on candidemia in COVID-19 patients.

Materials and methods: The baseline characteristics, as well as laboratory and clinical findings of candidemia and non-candidemia patients, were compared. Candidemia was defined as the isolation of Candida spp. from blood cultures. The isolates were identified by VITEK® 2 (bioMérieux, France) commercial method. Antifungal susceptibility was assessed using the E-test method. Univariate and multiple binary logistic regression analyses were performed to compare the variables.

Results: In total, 126 patients with the COVID-19 disease were included. Candidemia was diagnosed in 44 (35%) of the patients. The number of patients with diabetes mellitus and chronic renal failure was higher in the candidemia group. In the candidemia group, the duration of ICU stay of patients, the 30-day mortality rate, mechanical ventilation therapy, and systemic corticosteroids (Prednisone) usage were significantly higher in candidemia patients. Moreover, the median white blood cell, neutrophils, and lactate dehydrogenase were higher in the candidemia group.Univariate and multiple binary logistic regression analyses were performed to compare the variables. Isolated species were identified as Candida albicans (n=12, 41%), Candida parapsilosis (n=7, 24%), Candida glabrata (n=6, 21%), Candida tropicalis (n=3, 10%), and Candida dublinensis (n=1, 3%). In total, three isolates of six C. glabrata species had dose-dependent sensitivity to fluconazole, and one C. parapsilosis was determined to be resistant.

Conclusion: The COVID-19 patients who are admitted to ICU have many risk factors associated with candidemia. The most common risk factors for the development of candidemia were mechanical ventilation, diabetes mellitus, neutrophilia, and low hemoglobin level. The most frequently isolated species was C. albicans. Moreover, caspofungin was found to be the most effective drug in vitro. No significant resistance pattern was detected against the isolated species. It should be noted that risk-stratified antifungal prophylaxis in the ICU is possible.

Background and purpose: The healthcare system in India collapsed during the second wave of the COVID-19 pandemic. A fungal epidemic was announced amid the pandemic with several cases of COVID-associated mucormycosis and pulmonary aspergillosis being reported. However, there is limited data regarding mixed fungal infections in COVID-19 patients. Therefore, we present a series of ten consecutive COVID-19 patients with mixed invasive fungal infections (MIFIs).

Materials and methods: Among COVID-19 patients hospitalized in May 2021 at a tertiary care center in North India, 10 cases of microbiologically confirmed COVID-19-associated mucormycosis-aspergillosis (CAMA) were evaluated.

Results: All patients had diabetes and the majority of them were infected with severe COVID-19 pneumonia (6/10, 60%) either on admission or in the past month while two were each of moderate (20%) and mild (20%) categories of COVID-19; and were treated with steroid and cocktail therapy. The patients were managed with amphotericin-B along with surgical intervention. In total, 70% of all CAMA patients (Rhizopus arrhizus with Aspergillus flavus in seven and Aspergillus fumigatus complex in three patients) survived.

Conclusion: The study findings reflected the critical importance of a high index of clinical suspicion and accurate microbiological diagnosis in managing invasive dual molds and better understanding of the risk and progression of MIFIs among COVID-19 patients. Careful scrutiny and identification of MIFIs play a key role in the implementation of effective management strategies.

Background and purpose: Although Aspergillus fumigatus and Aspergillus flavus are more commonly implicated with ocular infections; there are some saprophytic species, such as Aspergillus nidulans (A. nidulans) which may occasionally lead to serious ocular infections. There is a paucity of data on ocular infections caused by A. nidulans. We report a case series of three ophthalmic infections caused by A. nidulans from a tertiary care eye center in North India.

Case report: Three cases of ophthalmic infections, including two cases of keratitis and one case of recurrent endophthalmitis caused by A. nidulans were diagnosed at the ocular microbiology section of a tertiary eye care center. One case of keratitis had a history of ophthalmic surgery and underlying diabetes mellitus. The case of recurrent endophthalmitis had undergone cataract surgery in the recent past. Diminution of vision was the most common presenting feature in all three cases. The microbiological diagnosis was made by conventional microscopy and culture techniques.

Conclusion: This case series illustrates the potential of uncommon fungal pathogens, such as A. nidulans to cause devastating ocular infections and has an emphasis on the importance of timely microbiological diagnosis in the management of such cases.

Background and purpose: Vulvovaginal candidiasis (VVC) is an opportunistic infection due to Candida species, one of the most common genital tract diseases among reproductive-age women. The present study aimed to investigate the prevalence of VVC among non-pregnant women and identify the epidemiology of the involved Candida species with the evaluation of antifungal susceptibilities.

Materials and methods: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was performed to identify Candida species isolated from the genital tract of 350 non-pregnant women. Moreover, antifungal susceptibility testing was performed according to the Clinical and Laboratory Standards Institute broth microdilution method guidelines (M27-A3 and M27-S4).

Results: Vaginal swab cultures of 119 (34%) women yielded Candida species. Candida albicans was the most frequently isolated species (68%), followed by Candida glabrata (19.2%). Voriconazole was the most active drug against all tested isolates showing an MIC50/MIC90 corresponding to 0.016/0.25 µg/mL, followed by posaconazole (0.031/1 µg/mL). Overall, resistance rates to fluconazole, itraconazole, and voriconazole were 2.4%, 4.8% and, 0.8% respectively. However, posaconazole showed potent in vitro activity against all tested isolates.

Conclusion: Results of the current study showed that for the effectual therapeutic outcome of candidiasis, accurate identification of species, appropriate source control, suitable antifungal regimens, and improved antifungal stewardship are highly recommended for the management and treatment of infection with Candida, like VVC.

Background and purpose: Due to the fact that fungal species, such as Aspergillus flavus and Aspergillus parasiticus produce carcinogenic and mutagenic aflatoxins and have the potential to produce fungal secondary metabolites, fungal contamination should be avoided. This study was conducted using the HPLC method and aimed to examine the fungal contamination of Isfahan hazelnuts in order to identify the presence of Aflatoxins.

Materials and methods: In total, 100 samples of hazelnuts were randomly collected from supermarkets in Isfahan. The samples were then cultured on Sabouraud dextrose agar media and analyzed to determine fungal contaminations. The aflatoxin analysis was carried out using the HPLC method.

Results: It was discovered that nine genera of fungi, namely Aspergillus, Penicillium, Rhizopus, Ulocladium, Alternaria, Drechselera, Trichothecium, Scopulariopsis, and Mucor were identified in 78% of the samples. Samples contaminated with Aspergillus flavus (22 samples) were studied to determine the presence of aflatoxin. The results showed that 16 (72.72%) of the samples were contaminated with AFB1, AFB2, and AFG2 and the mean concentrations were 0.926, 0.563, and 0.155 ng/g, respectively.

Conclusion: Some parameters that affect mycotoxin production are temperature, food substrate, the strain of the mold, and other environmental factors. Due to the toxigenic quality of some of these fungi and their hazard to human health, it is crucial that fungal contamination and aflatoxin identification tests are carried out before certain products are made available to the mass market.

Background and purpose: Histoplasma capsulatum is the cause of a prevalent fungal disease in certain regions in the United States of America, like Ohio and the Mississippi River. Its clinical manifestations range from asymptomatic to life-threatening diseases, according to the immune system. A definitive diagnosis is made by biopsy.

Case report: Two middle-aged brothers presented with a nine-day history of severe progressive dyspnea. Both were living in Cincinnati, Ohio, and encountered bird droppings 7 days prior to symptoms while working on a roofing project. It should be mentioned that they were not wearing masks. After extensive testing, they were diagnosed with acute pulmonary histoplasmosis. Both were successfully treated with azole-derivative fungal therapy.

Conclusion: This is the first case of histoplasmosis acquired through occupational exposure related to roofing and is unique given the two patients were siblings.

Background and purpose: The pandemic of COVID-19 has caused a worldwide health crisis. Candidemia is a potentially lethal condition that has not yet been enough discussed in patients with COVID-19. The current study aimed to investigate the prevalence of candidemia among Iranian COVID-19 patients and characterize its causative agents and the antifungal susceptibility pattern.

Materials and methods: The present cross-sectional survey was carried out from March 2020 to March 2021 at Imam Khomeini Hospital, Tehran, Iran. Blood specimens were obtained from patients with confirmed coronavirus infection who also had criteria for candidemia and were examined for any Candida species by conventional and molecular techniques. Susceptibility of isolates to amphotericin B, voriconazole, itraconazole, fluconazole, caspofungin, and 5-flucytosine was tested using the CLSI broth dilution technique.

Results: In total, 153 patients with COVID-19 were included and candidemia was confirmed in 12 (7.8 %) of them. The majority of patients were ≥ 50 years of age (n=9) and female (n=8). Moreover, 6 out of the 12 patients were diabetic. The presence of central venous catheters, broad-spectrum antibiotic therapy, ICU admission, and mechanical ventilation was observed in all patients. The C. albicans (n=7, 58.3 %) and C. dubliniensis (n=2, 16.7%) were the most common isolated species. Amphotericin B and 5-flucytosine were the most active drugs. Despite antifungal treatment, 4 out of 12 patients (33.3 %) died.

Conclusion: Due to the high mortality, the early diagnosis and proper treatment of candidemia are essential requirements for optimal clinical outcomes in COVID-19 patients.