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Interleukin-6 (IL-6) is a cytokine with pleiotropic effects that might also influence the virulence traits of some microorganisms, but its direct influence over Candida spp. is currently unknown. The objective of the study is to determine the influence of IL-6 (250 pg/ml) on the growth rate and biofilm formation of C. albicans, C. parapsilosis, C. krusei, C. auris, and C. guilliermondii, as well as to analyze the influence of this citokine on the expression of three virulence genes (ALS3, HSP70, SAP2), respectively on the germ tube formation ability of C. albicans. The influence of IL-6 on growth rate was assessed by incubating the fungal cells in presence of IL-6 for 48 hours and assessing the optical density of the samples at five timepoints. The biofilm production in presence of IL-6 was studied in microtiter plates, using crystal-violet assay, the intensity of biofilms being evaluated by spectrophotometry. The expression of ALS3, HSP70, and SAP2 in C. albicans was studied by RT-PCR, reported to ACT1 housekeeping gene. The germ-tube test was performed to assess the influence of IL-6 on the filamentation rate of C. albicans. All test results were normalized against control, without added IL-6. The results showed that IL-6 influences the growth rate of C. albicans, C. parapsilosis, C. krusei, C. auris, and C. guilliermondii in a time-dependent way. Also, IL-6 inhibited the formation of biofilms for C. albicans and C. guilliermondii. In C. albicans cells, IL-6 induced upregulation of ALS3 and HSP70, while it down-regulated the SAP2 gene. IL-6 did not influence the germ-tube formation in C. albicans. In conclusion, IL-6 might exert, in vitro, direct effects on the virulence traits of Candida spp., and its influence is dependent on the exposure time. Non-albicans Candida species presented particular responses to IL-6. [ABSTRACT FROM AUTHOR]

Multilocus sequence typing is a powerful method for genotyping of clinical isolates of Candida albicans. 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. 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. 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. 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. [ABSTRACT FROM AUTHOR]

Fungal virulence factors represent a strategy for the design of new compounds with effective activities against Candida spp. Dichloromethyl-4-chloro-3-nitrophenylsulfone (named Compound 1) and chlorodibromomethyl-4-hydrazino-3-nitrophenylsulfone (Compound 2) versus Candida albicans virulence factors ( SAP2 expression and adhesion to Caco-2 cell line) were investigated. Candida albicans SC5314 and its mutants: Δsap9, Δsap10, Δsap9/10 were used. MICs of the Compounds (concentrated at 0.0313-16 µg/ml) were determined using M27-A3. Percentage of cell inhibition was assessed spectrophotometrically (OD) after 48 h at 35 °C. The SAP2 expression was analyzed with the use of RT-PCR; relative quantification was normalized against ACT1 in cells grown in YEPD and on Caco-2. Adherence assay of C. albicans to Caco-2 was performed in a 24-well-plate. Compound 1 showed higher activity (% = 100 at 4 µg/ml) than Compound 2 (MIC = 16 µg/ml). Dichloromethyl at the para position of the phenyl ring exerted anti- Candidal potential. Under Compound 1, SAP2 was down-regulated in all the strains ( P ≤ 0.05). Conversely, SAP2 was over-expressed in Δsap9- 10 (untreated cells) compared with the wild-type. The Compounds significantly affected adherence to epithelium ( P ≤ 0.05). The tested sulfones interfered with the adhesion of C. albicans cells to the epithelial tissues without affecting their viability after 90-min of incubation. The Compounds' mode of action was attributed to the reduced adhesiveness and the lower SAP2 expression. Saps9-10 play a role in C. albicans adhesion and they can be involved in the sulfone resistance mechanisms. [ABSTRACT FROM AUTHOR]

Background: Smokers are more prone to oral infections than are non-smokers. Cigarette smoke reaches the host cells but also microorganisms present in the oral cavity. The contact between cigarette smoke and oral bacteria promotes such oral diseases as periodontitis. Cigarette smoke can also modulate C. albicans activities that promote oral candidiasis. The goal of this study was to investigate the effect of cigarette smoke condensate on C. albicans adhesion, growth, and biofilm formation as well as the activation of EAP1, HWP1 and secreted aspartic protease 2. Results: Cigarette smoke condensate (CSC) increased C. albicans adhesion and growth, as well as biofilm formation. These features may be supported by the activation of certain important genes. Using quantitative RT-PCR, we demonstrated that CSC-exposed C. albicans expressed high levels of EAP1, HWP1 and SAP2 mRNA and that this gene expression increased with increasing concentrations of CSC. Conclusion: CSC induction of C. albicans adhesion, growth, and biofilm formation may explain the increased persistence of this pathogen in smokers. These findings may also be relevant to other biofilm-induced oral diseases. [ABSTRACT FROM AUTHOR]

Systemic candidiasis is the fourth most common bloodstream infection in ICU patients worldwide. Although C. albicans is a predominant species causing systemic candidiasis, infections caused by non-albicans Candida (NAC) species are increasingly becoming more prevalent globally along with the emergence of drug resistance. The diagnosis of systemic candidiasis is difficult due to the absence of significant clinical symptoms in patients. We investigated the diagnostic potential of recombinant secreted aspartyl proteinase 2 (rSap2) from C. parapsilosis for the detection of Candida infection. The rSap2 protein was successfully cloned, expressed and purified using Ni-NTA chromatography under denaturing conditions using an E. coli-based prokaryotic expression system, and refolded using a multi-step dialysis procedure. Structural analysis by CD and FTIR spectroscopy revealed the refolded protein to be in its near native conformation. Immunogenicity analysis demonstrated the rSap2 protein to be highly immunogenic as evident from significantly high titers of Sap2-specific antibodies in antigen immunized Balb/c mice, compared to sham-immunized controls. The diagnostic potential of rSap2 protein was evaluated using immunoblotting and ELISA assays using proven candidiasis patient serum and controls. Immunoblotting results indicate that reactivity to rSap2 was specific to candidiasis patient sera with no cross reactivity observed in healthy controls. Increased levels of anti-Sap2-specific Ig, IgG and IgM antibodies were observed in candidiasis patients compared to controls and was similar in sensitivity obtained when whole Candida was used as coating antigen. In summary, the rSap2 protein from C. parapsilosis has the potential to be used in the diagnosis of systemic candidiasis, providing a rapid, convenient, accurate and cost-effective strategy. [ABSTRACT FROM AUTHOR]