Faculty and Research

Candida Biofilm Prevention and Treatment

Dr. Krystyna Konopka

We are interested in the susceptibility of C. albicans biofilms developed on denture acrylic to antifungals and histatin 5. C. albicans, a member of the normal microbial flora, is a medically important opportunistic pathogen, especially in immunocompromised individuals. Oral candidiasis is a frequent superficial infection associated with mechanical/traumatic factors and immunosupression.

In the oral cavity, most microorganisms are found not as planktonic, free-living cells, but as attached, complex structured communities surrounded by a polysaccharide matrix, known as biofilms. The majority of manifestations of both mucosal and systemic candidiasis are associated with biofilm formation on inert or biological surfaces. C. albicans biofilms are highly resistant to antifungal and antimicrobial agents. Biofilm-related resistance in denture stomatitis may explain the high recurrence rates often observed in this type of infection.

Histatins are small histidine-rich cationic peptides that are secreted by the parotid and sub-mandibular salivary glands and are present in saliva at concentrations of 50-425 µg/ml. They represent a group of antimicrobial peptides with some antibacterial properties and significant antifungal properties. Histatin 1, histatin 3, and histatin 5 (Hst 5) are the major histatins found in saliva. In vitro, Hst 5 is the most potent member of the family that kills pathogenic Candida species from 90% to 100% at physiological concentrations. The mechanisms by which salivary histatins exert their anticandidal activity are not completely understood.

The antifungal potential of histatins can be utilized by including them in topical gels or denture acrylic. The ability to localize histatins in dentures, or other synthetic oral implants, could be beneficial because histatin may prevent colonization of the material itself, and releasing it from the denture may also contribute to the control of yeast in the oral cavity.

Krystyna Konopka, kkonopka@pacific.edu, 415.929.6571