Genotyping of Candidaalbicans isolates from oropharyngeal candidiasis in head and neck cancer patients in Iran: Molecular epidemiology and SAP2 gene expression.

OBJECTIVE: Multilocus sequence typing is a powerful method for genotyping of clinical isolates of Candidaalbicans. Cross-contamination between the patients is an important reason for nosocomial infections. Oropharyngeal candidiasis (OPC) caused by C. albicans is an important problem in patients with head and neck cancer, in Cancer Institute of Tehran. Here we studied the endemic genotypes of C. albicans isolates and the relationship between geographic distributions, potential cross-contaminations and the expression of SAP2 gene, an important gene in oral candidiasis, with MLST groups. MATERIAL AND METHODS: A total of 32 clinical strains of C. albicans isolated from head and neck cancer patients with oropharyngeal candidiasis were subjected to MLST analysis and SAP2 gene expression was analyzed by Real-time PCR. RESULTS: We identified 75 polymorphic sites in 7 loci of C. albicans isolates and 30 diploid sequence types which 27 of them were found as new. After eBURST analysis, our results determined that CC 124 was the most prevalent group among all CCs. SAP2 gene showed high expression in almost all OPC patients' isolates, compared to the control. CONCLUSION: We found few genetically-related as well as identical isolates among the 32 Candida strains which indicated low cross-contaminations among the patients. There was no relationship between C. albicans MLST profiles and their geographic distribution, cancer type and SAP2 gene expression. This lack of correlation was possibly due to the small understudy population; hence, finding more relevance requires studies with a higher number of samples.

Oropharyngeal candidiasis in head and neck cancer patients in Iran: Species identification, antifungal susceptibility and pathogenic characterization.

OBJECTIVE: Oropharyngeal candidiasis (OPC) is the most frequent opportunistic fungal infection in head and neck cancer patients. This study was done to identify the Candida species, which cause OPC, and to evaluate their antifungal susceptibility pattern and pathogenic characteristics in Iranian head and neck cancer patients treated by radiotherapy. MATERIAL AND METHODS: The oral clinical samples were determined by culturing on CHROMagar, carbohydrate assimilation and ITS sequencing methods. Biofilm formation, phospholipase and proteinase activity and antifungal susceptibility were examined too. RESULTS: Among 54 patients with confirmed OPC, 39 (72.22%) patients were male and 15 (27.77%) were female. The most frequently Candida species from a total of 60 isolates was C. albicans (53.3%), followed by C. tropicalis (21.66%), C. glabrata (15%), C. kefyr (5%) and C. dubliniensis (1.66%). All the isolates were high-producers of biofilm. All of Candida isolates were proteinase positive and 47 isolates (81.04%) represented phospholipase activity. The maximum and minimum rates of antifungal resistance belonged to ketoconazole (93.75% of C. albicans and 89.28% of Candida non-albicans) and fluconazole (62.50% and 42.85% of C. albicans and Candida non-albicans), respectively. The most effective antifungal against all candida isolates was fluconazole. CONCLUSION: Our data can estimate abundance of OPC in male and female head and neck cancer patients and is helpful to use effective strategies for antifungal treatment, prophylaxis, and preventive therapies in these patients.

Rhinocerebral mucormycosis due to Rhizopus oryzae in a diabetic patient: a case report.

Mucormycosis is an opportunistic fulminant fungal infection, which affects nose and paranasal sinuses by direct invasion or through the blood vessels mainly in diabetic and immunocompromised patients. In the present study, a rhino-orbito-cerebral mucormycosis in a 24-year-old female with diabetes mellitus as underlying disease was reported. Computed tomography (CT scan) demonstrated an increase in the soft tissue densities in the left nasal cavity, maxillary and ethmoid sinuses and destruction of the antral wall with soft tissue densities in the pterygopalatine fossa and retromaxillary fissure. In histopathology, wide ribbon-shape non-septate hyphae were seen in tissue sections stained with hematoxylin-eosin (H&E). The etiologic fungus isolated from tissue biopsy on mycological media was identified by the amplification and sequencing of the 5.8S RNA gene and of the adjacent internal transcriber spacer domains, ITS1/ITS4, as Rhizopous oryzae. Recognition of the unique patterns of this high mortality rhinocerebral fungal infection in patients with diabetes is a key to early diagnosis and successful treatment.

Effect of Curcumin on Aspergillus parasiticus Growth and Expression of Major Genes Involved in the Early and Late Stages of Aflatoxin Biosynthesis.

BACKGROUND: The effect of curcumin as a natural safe compound with different biological activities was examined on fungal growth and aflatoxin production in Aspergillus parasiticus NRRL 2999. METHODS: The fungus was cultured in presence of serial two-fold concentrations of curcumin (125-2000 µg/ml) in yeast extract sucrose broth for 3 days at 28°C. Mycelia dry weight was determined as an index of fungal growth, while aflatoxin production was assessed by high performance liquid chromatography (HPLC). The expression of ver-1, nor-1, pksA, omtA and aflR genes in aflatoxin biosynthetic pathway was evaluated by real time PCR. RESULTS: Curcumin strongly inhibited aflatoxin B(1) production in the range of 26.6 to 94.9% by serial two-fold concentrations from 125 to 2000 µg/ml. Fungal growth was also inhibited by the compound in the range of 34.0 to 60.8%. Analysis of the expression of aflatoxin pathway genes by real time PCR showed that curcumin inhibited the expression of ver-1, nor-1, pksA, omtA and aflR genes at concentrations of 250 and 1000 µg/ml. In concentration of 1000 µg/ml, gene expression was reduced by 31.3%, 44.6%, 57.1% 110.9% and 286.7% accordingly. Reduction in the expression of aflatoxin biosynthesis genes was significant only for aflR. In ferric reducing ability of plasma (FRAP) assay, curcumin showed strong antioxidant activity at all concentrations tested. CONCLUSION: Curcumin may be employed successfully as a good candidate in controlling of toxigenic fungal growth on food and feed and subsequent contamination with aflatoxins in practice.