Glabridin triggers over-expression of MCA1 and NUC1 genes in Candida glabrata: Is it an apoptosis inducer?

The growing trends of emergence of antifungal-resistant Candida strains has recently been inspired the researchers to design new antifungal agents with novel mechanisms of action. Glabridin is an originally natural substrate with multiple biological activities which propose it as a novel anticancer, antimicrobial and antifungal agent. In the present study, the antifungal effect of glabridin against Candida glabrata isolates and its possible mechanism of action were investigated. The minimum inhibitory concentrations (MIC) for glabridin against fluconazole-resistant and fluconazole-SDD strains of C. glabrata were investigated using the Clinical and laboratory standards institute document M27-A3 and M27-S4 as a guideline. Possible alternations in the expression of two critical genes involved in yeast apoptosis, MCA1 and NUC1, were assayed by real-time PCR. DNA damage and chromatin condensation was investigated using DAPI staining. Although glabridin led to a significant decrease in MICs against fluconazole-resistant C. glabrata (MIC50: 8µg/mL), no significant decreased was shown for fluconazole-SDD strains. Therefore, a distinct azole-independent mechanism could be responsible for the inhibitory activity of glabridin. Overexpression of MCA1 and NUC1 genes in addition to DNA damage and chromatin condensation suggesting the involvement of apoptosis signaling in C. glabrata stains exposed to glabridin. This study suggests that glabridin might be considered as a novel naturally originated agent to fight against fluconazole-resistance C. glabrata strains.

A real time PCR assay on blood for diagnosis of invasive candidiasis in immunocompromised patient.

BACKGROUND AND PURPOSE: Invasive candidiasis (IC) is a significant cause of morbidity and mortality in patients with hematologic disorders and bone marrow transplant recipients. Rapid, specific and sensitive test for the timely accuracy in immunocompromised patients to reduce mortality rates and prevent IC progress is necessary. We established a real-time PCR assay on blood for the diagnosis and differentiation of the causative Candida species. MATERIALS AND METHODS: Whole blood samples were collected twice, from 72 patients for Real Time PCR and blood culture assays. The primers and hybridization probes were designed to potentiate the specific sequence of 18S rRNA genes using Light Cycler system and Fluorescence Resonance Energy Transfer (FERT). The patients with hematologic malignancies and bone marrow transplant recipients were evaluated for IC based on the revised European Organization for Research and Treatment of Cancer/ Mycoses Study Group (EORTC/MSG) criteria. RESULTS: From 2009 to 2011, 72 patients with hematologic malignancies and bone marrow transplant recipients were evaluated for IC. The female to male ratio was 27:45; the mean age was 32.1 years. The most common malignancy in this patient was acute myeloid leukemia (AML) (27.8%) and acute lymphoblastic leukemia (ALL) (26.4%). Out of 72 patients, 11 patients (15.3%) had positive real time PCR /probe results. Based on the melting temperature (Tm) analysis, 5 (45.4%) C. krusei, 3 (27.2%) C. tropicalis, 2 (18.1%) C. parapsilosis and 1 C. albicans (9%) were identified. According to the revised EORTC / MSG, 1 patient (9%) and 10 patients (91%) were defined as proven and possible groups of IC, respectively. The mortality rate in proven and possible IC patient was found 54.5%. CONCLUSION: The established Real-time PCR/FRET probe assay is an appropriate diagnostic tool for the detection of Candida species DNA and the management of patients suffering from hematologic malignancies and bone marrow recipient are at risk for IC.

Green synthesis of silver nanoparticles: Advantages of the yeast Saccharomyces cerevisiae model.

BACKGROUND AND PURPOSE: Microorganism-based synthesis of nanostructures has recently been noted as a green method for the sustainable development of nanotechnology. Nowadays, there have been numerous studies on the emerging resistant pathogenic bacteria and fungal isolates, the probable inability of bacteria and fungi to develop resistance against silver nanoparticles' (SNPs) antibacterial, antifungal, antiviral and, particularly antibacterial activities. In this study, we aim to use the yeast Saccharomycescerevisiae model for synthesis of SNPs and to investigate its antifungal activity against some isolates of Candidaalbicans. MATERIALS AND METHODS: A standard strain of S.cerevisiae was grown in liquid medium containing mineral salt; then, it was exposed to 2 mM AgNO3. The reduction of Ag+ ions to metal nanoparticles was virtually investigated by tracing the color of the solution, which turned into reddish-brown after 72 hours. Further characterization of synthesized SNPs was performed afterwards. In addition, antifungal activity of synthesized SNPs was evaluated against fluconazole-susceptible and fluconazole-resistant isolates of Candidaalbicans. RESULTS: The UV-vis spectra demonstrated a broad peak centering at 410 nm, which is associated with the particle sizes much less than 70 nm. The results of TEM demonstrated fairly uniform, spherical and small in size particles with almost 83.6% ranging between 5 and 20 nm. The zeta potential of SNPs was negative and equal to -25.0 (minus 25) mv suggesting that there was not much aggregation. Silver nanoparticles synthesized by S.cerevisiae, showed antifungal activity against fluconazole-susceptible and fluconazole-resistant Candida albicans isolates, and exhibited MIC90 values of 2 and 4 µg/ml, respectively. CONCLUSION: The yeast S. cerevisiae model demonstrated the potential for extracellular synthesis of fairly monodisperse silver nanoparticles.

Aspergillus colonization in patients with chronic obstructive pulmonary disease.

BACKGROUND AND PURPOSE: Chronic obstructive pulmonary disease (COPD) has been recognized as a risk factor for invasive aspergillosis. Airway colonization by Aspergillus species is a common feature of chronic pulmonary diseases. Nowadays, the incidence of COPD has increased in critically ill patients. The aim of the present study was to isolate and identify Aspergillus colonies in the respiratory tract of COPD patients. MATERIALS AND METHODS: This study was performed on 50 COPD patients, who were aged above 18 years, and were in intensive care units of three hospitals in Sari, Iran, for at least six days. All the samples obtained from sputum, bronchoalveolar lavage, and tracheal aspirates were cultured for fungi each week. According to the conventional techniques, Aspergillus isolates were initially based on growth and standard morphological characteristics. To confirm the identification of grown Aspergillus, the partial beta-tubulin gene was sequenced using specific primers. RESULTS: A total of 50 patients, who met our inclusion criteria, were enrolled in the study during 2012-14. The results showed that 27 (54%) and 23 (46%) of the participants were male and female, respectively. The majority of the patients developed dyspnea followed by hemoptysis, chest pain, and high fever. Corticosteroids and broad-spectrum antibacterial agents were administered to 75% and 80% of the patients, respectively. Based on the conventional and molecular approaches, A. fumigatus (seven cases; 43.7%), A. flavus (five cases; 31.2%), A. niger (one case; 6.2%), A. terreus (one case; 6.2%), A. orezea (one case; 6.2%), and A. tubingensis (one case; 6.2%) were recovered. CONCLUSION: Recovery of Aspergillus species from the respiratory tract of COPD patients with pneumonia indicates two possibilities: either colonization or invasive aspergillosis.

Evaluation of bacterial and fungal contamination in the health care workers' hands and rings in the intensive care unit.

INTRODUCTION: Nosocomial infections remain a major challenge to the health care system and result in significant mortality, morbidity, and economic burden. Intensive care unit (ICU) patients are at great risk of acquiring nosocomial infections. The objective of this study was to determine the contamination rate (bacterial and fungal) of the health care workers' (HCWs') hands and ring in ICU. METHODS: All health care workers were screened during the day shift in Emam hospital ICU. After obtaining informed consent, convenience samples of HCWs' hands and rings were cultured on specific media during their routine work hours, always after a patient care episode. The fungal and bacterial isolates were identified using standard microbiological procedures. RESULTS: A total of 40 subjects were selected in this study (28 females, 12 males). The rate of contamination of hands and rings was observed in 73.1%. Most of isolates are known to cause nosocomial infections which included: 23% staphylococci, 7.9% Klebsiella spp., 4.7% Enterobacter spp., 3.9% Escherichia coli, 3.1% Acinetobacter spp., 2.3% Pseudomonas spp., and 27.7% were colonized with fungi. The fungal isolates were 16.6% Candida spp., 3.9% Rhodotorula spp., 3.1% Aspergillus niger, and 3.9% Aspergillus flavus. CONCLUSION: According to these results HCWs' hands and their rings were contaminated with various types of microorganisms. Medical and hospital personals must follow careful hand-washing techniques to minimize transmission of disease and should remove rings, watches, and bracelets before washing their hands and entering the ICU.