Anti-biofilm properties of eucalyptol in combination with antifungals against Candida albicans isolates in patients with hematological malignancy.

Oral candidiasis is a fungal infection caused mainly by Candida albicans and it is a major problem among hematologic malignancy patients. Biofilm formation is an attributable factor to both virulence and drug resistance of Candida species. The aim of the study was to evaluate the biofilm-producing ability of oral C. albicans isolates and to evaluate the inhibitory activity of eucalyptol on Candida biofilm, alone and in combination with antifungal agents. Samples were collected from the oral cavity of 106 patients with hematologic malignancy. The isolated yeasts were identified by PCR-sequencing. Then C. albicans isolates were analyzed for their biofilm-producing ability by crystal violet staining and MTT assay. The minimum biofilm inhibition concentrations (MBIC) of eucalyptol, amphotericin B, itraconazole, and nystatin and the in vitro interaction of eucalyptol with these drugs were tested according to CLSI-M-27-A3 protocol and checkerboard methods, respectively. From 106 patients, 50 (47.2%) were confirmed for oral candidiasis [mean ± SD age 39 ± 14 years; female 31 (62%) and male 19 (38%)]. C. albicans was isolated from 40 of 50 (80%) patients. From 40 C. albicans isolates, 24 (60%) and 16 (40%) were moderate and weak biofilm producer, respectively. The geometric mean MBIC of amphotericin B, itraconazole, nystatin and eucalyptol were 3.93 µg/mL, 12.55 µg/mL, 0.75 µg/mL and 798 µg/mL, respectively. Eucalyptol interacted synergistically with amphotericin B, itraconazole and nystatin against 12.5, 10, and 22.5% of isolates, respectively. Eucalyptol demonstrated promising activity against biofilm of C. albicans when tested alone or combined with antifungal drugs.

Activities of Nanoparticles Against Fluconazole-Resistant Candida parapsilosis in Clinical Isolates.

Candida parapsilosis is a non-albicans Candida spp. associated with bloodstream infections in critically ill patients. Failure to treat it effectively due to delay in diagnosis often leads to serious illnessess. The present research aimed to investigate the antifungal activities of nanoparticles (NPs) against fluconazole-resistant C. parapsilosis strains. Ten strains were used from archived clinical isolates. Antifungal activities of NPs were examined based on the Clinical and Laboratory Standards Institute (M27-A3/S4) guideline. The morphological changes of strains exposed to each NP were observed by scanning electron microscope (SEM). The effect of NP on the membrane permeability of C. parapsilosis and the viability of the cells was assessed using the confocal laser scanning microscopy and 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, respectively. The cytotoxicity was evaluated against three mammalian cell lines. Minimum Inhibitory Concentration of NPs of 10 strains was in the concentration range of 0.5-4 µg/mL; these results were confirmed with the viability test. The antifungal activity of synthesized silver NPs (AgNPs) against resistant C. parapsilosis was greater in comparison with the gold NPs (AuNPs). The SEM images indicated a difference in the fungal morphology of the fungi. The propidium iodide uptake by C. parapsilosis cells showed concentration-dependent mortality in NPs treatment with a confocal laser scanning microscope. There was a notable difference (p < 0.01) in the cell viability in the concentration range of 0.5-4 µg/mL between NPs based on the MTT assay. In addition, these NPs exhibited very low toxicity for three mammalian cell lines, specially at 0.5 µg/mL. AgNPs and AuNPs had fungicidal activities against fluconazole-resistant C. parapsilosis strains. It is crucial to have knowledge based on fundamental research to find new ways to overcome resistant microorganisms.

Acute invasive fungal rhinosinusitis: Molecular identification and update in management of frozen section biopsy.

The clinical diagnosis of Acute Invasive Fungal Rhinosinusitis (AIFRS) is technically difficult because it presents with non-exclusive and nonspecific clinical symptoms. Laboratory confirmation (usually via histopathologic techniques such as formalin-fixed paraffin-embedded (FFPE)) is necessary but it is time-consuming, despite the urgent need for timely diagnosis of AIFRS for effective management. This study aimed to investigate the sensitivity and specificity of the GMS frozen-section biopsy in the diagnosis of AIFRS and compare the same with that of different tissue staining methods to provide valid decision-grounds that may guide clinicians in prompt diagnosis of acute fungal invasive rhinosinusitis. A cross-sectional study was conducted in the Medical Mycology Laboratory, Faculty of Medicine, Iran University of Medical Sciences between 2018 and 2020 on 200 patients with suspected AIFRS referred to Baqiyatallah and Imam Khomeini Hospital, Tehran. All patients were subjected to diagnostic nasal endoscopy and computed tomography (CT) scan of paranasal sinuses. Magnetic resonance imaging (MRI) was done in cases of suspected intracranial extension. After screening by routine mycological examination, the diagnosis was confirmed using complementary molecular methods. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the frozen-section biopsy were also compared with FFPE. Of the 200 suspect patients, 47 cases (23.5%) met the criteria for AIFRS. Species of the genus Aspergillus were the predominant 27 (57.4%) followed by Mucorales species 10 (21.3%), and Fusarium spp 3 (6.4%). Also, 3 cases (6.4%) of co-infection due to Aspergillus/Rhizopus were reported. The accuracy, sensitivity, specificity, PPV, and NPV of frozen section assessments were 99.5%, 97.9%, 100%, 100% and 99.3%, respectively. For GMS frozen-section alone, sensitivity, specificity, NPV, and PPV was 100%. Overall, the calculated accuracy of FFPE was 98.5%, sensitivity was 94%, specificity was 100%, PPV was 100%, and NPV was 98.1%. Examination of the frozen-section biopsy is a highly predictive tool for a rapid and effective diagnosis of patients with suspected AIFRS. We observed that GMS frozen-section is a fast and reliable exam to confirm the diagnosis of fungal invasion, with good accuracy, sensitivity, and specificity compared to the gold-standard FFPE biopsy.

Comparison of Antifungal Properties of Gold, Silver, and Selenium Nanoparticles Against Amphotericin B-Resistant Candida glabrata Clinical Isolates.

BACKGROUND: The present study aimed to investigate the antifungal activity of Nanoparticles (NPs) against amphotericin B-resistant Candida glabrata (C. glabrata) strains. METHODS: Twelve resistant (C. glabrata) strains were isolated from archived clinical isolates. Antifungal activity was conducted according to Clinical and Laboratory Standards Institute's (CLSI) guidelines, document M27-A3/S4. The Scanning Electron Microscope (SEM) was used to observe the morphological changes of strains exposed to each nanoparticle. RESULTS: Minimum Inhibitory Concentration (MIC) of nanoparticles of all strains was in the concentration range of 0.125 to 0.5 µg/Ml. The synthesized Ag-NPs showed superior antifungal activity against (C. glabrata) compared to Se-NPs and Au-NPs. The scanning electron microscope images revealed the difference in the fungal morphology between the untreated and treated fungi with nanoparticles. CONCLUSION: The Ag-NPs, followed by Se-NPs synthesized, revealed significant anti-fungal activity against resistance regardless of their antifungal-resistant mechanisms.