Candida glabrata Binding to Candida albicans Hyphae Enables Its Development in Oropharyngeal Candidiasis

Oral mucositis caused by Candida glabrata biofilms: failure of the concomitant use of fluconazole and ascorbic acid

OBJECTIVES

Candida glabrata is becoming one of the most prevalent pathogenic yeasts in cases of oral diseases. Mucositis is an recurrent oral infection in immunocompromised patients, and the actual guidelines recommend the use of fluconazole (Flu) for many cases. However, the azole resistance by C. glabrata is renowned, causing a reduced therapeutic response, especially when it occurs in biofilms. In this study, we performed an in vitro evaluation of an alternative pharmacotherapy for C. glabrata biofilm infections, combining ascorbic acid (AA) with Flu. AA is recognized for degrading β-glucans, an important compound of the biofilm matrices, which prevent drug diffusion.

MATERIALS AND METHODS

Routine clinical 30 or 40 mg/l doses of Flu were applied to C. glabrata biofilms simultaneously with 200 or 300 mg/l of AA.

RESULTS

The results showed that this combination effectively promoted the degradation of the biofilm network, but unfortunately, also stimulated the growth of the yeasts population due to release of several glucose monomers during β-glucans hydrolysis.

DISCUSSION

AA lead to the hydrolysis of the β-glucans of the matrix, liberating glucose molecules which are used as carbon souce by the yeasts, thus suppressing the desired antifungal effect of the drug combination with Flu.

CONCLUSIONS

Unlike to what happens in treatment of bacterial infection, AA should not be used together with Flu in the treating oral mucositis caused by Candida.

Enterohemorrhagic Escherichia coli promotes the invasion and tissue damage of enterocytes infected with Candida albicans in vitro

The principal aim of this study was to investigate the in vitro co-infection of Caco-2 cells with Candida albicans and enterohemorrhage Escherichia coli (EHEC). The ability of both species to colonize or invade the Caco-2 cells was evaluated by indirect immunofluorescence and inverted microscopy. The damage to Caco-2 cells was evaluated by measuring lactate dehydrogenase (LDH) activity. C. albicans virulence gene expression (HWP1, ALS3, PLB1, SAP4, and EFG1) was evaluated by quantitative real-time polymerase chain reaction (qRT-PCR). Compared to single infections with enterohemorrhage Escherichia coli or C. albicans, a co-infection colonized or invaded Caco-2 cells more quickly, and C. albicans tended to accumulate more easily, accompanied by the upregulation of related genes. In addition, the LDH activity in the co-infected group was higher than in cells infected with C. albicans or with enterohemorrhage Escherichia coli, accompanied by the upregulation of toxicity-related genes. Using Caco-2 cells as an infection model, this study demonstrated that co-infecting in vitro enterocytes with C. albicans and enterohemorrhage Escherichia coli enhanced the invasiveness and tissue damaging effects of C. albicans.

Cell biology of Candida albicans-host interactions

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The cell biology of Candida albicans is adapted both for life as a commensal and as a pathogen.

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C. albicans can either downregulate or upregulate virulence properties in the human host.

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This fungus modulates the activity of phagocytes to enable its own survival.

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Candida is metabolically flexible enabling it to survive in multiple niches in the host.

Candida albicans is a commensal coloniser of most people and a pathogen of the immunocompromised or patients in which barriers that prevent dissemination have been disrupted. Both the commensal and pathogenic states involve regulation and adaptation to the host microenvironment. The pathogenic potential can be downregulated to sustain commensalism or upregulated to damage host tissue and avoid and subvert immune surveillance. In either case it seems as though the cell biology of this fungus has evolved to enable the establishment of different types of relationships with the human host. Here we summarise latest advances in the analysis of mechanisms that enable C. albicans to occupy different body sites whilst avoiding being eliminated by the sentinel activities of the human immune system.

The vaginal mycobiome: A contemporary perspective on fungi in women's health and diseases

Most of what is known about fungi in the human vagina has come from culture-based studies and phenotypic characterization of single organisms. Though valuable, these approaches have masked the complexity of fungal communities within the vagina. The vaginal mycobiome has become an emerging field of study as genomics tools are increasingly employed and we begin to appreciate the role these fungal communities play in human health and disease. Though vastly outnumbered by its bacterial counterparts, fungi are important constituents of the vaginal ecosystem in many healthy women. Candida albicans, an opportunistic fungal pathogen, colonizes 20% of women without causing any overt symptoms, yet it is one of the leading causes of infectious vaginitis. Understanding its mechanisms of commensalism and patho-genesis are both essential to developing more effective therapies. Describing the interactions between Candida, bacteria (such as Lactobacillus spp.) and other fungi in the vagina is funda-mental to our characterization of the vaginal mycobiome.