knova2@uky.edu

Periodontal (gum) disease affects a large percentage of the US population. Work in our laboratory focuses on pathogenic properties of microorganisms associated with periodontal disease. Specific projects are outlined below:

1) Characterization of the mechanisms by which Actinobacillus actinomycetemcomitans (a pathogen associated with certain forms of periodontal disease) transports potential virulence factors from the intracellular to the extracellular environment.

2) Evaluation of bacterial typing systems in the genetic characterization of oral pathogens. Bacterial typing systems are fundamental for epidemiologic study of colonizing clones or for tracing the transmission of microorganisms from one individual to another. There is evidence that using multiple typing systems is more reliable and provides a higher discriminatory power than any one typing system alone in genetic analysis of bacteria. We hypothesized that a select panel of typing systems previously not used with oral pathogens would allow discrimination of different bacterial species as well as different strains within a given species. We have been investigating four polymerase chain reaction (PCR)-based methods in examining genetic variability of eight pathogens associated with periodontitis (Porphyromonas gingivalis; Prevotella intermedia; Actinobacillus actinomycetemcomitans; Tannerella forsynthesis; Treponema denticola; Peptostreptococcus micros; Fusobacterium nucleatum; Selenomonas noxia). The methods were: 1) arbitrarily-primed (AP)-PCR; 2) repetitive extragenic palindromic (REP)-PCR; 3) enterobacterial repetitive intergenic consensus (ERIC)-PCR; and 4) BOX-PCR.

3) Evaluation of the efficacy of antimicrobial peptides against oral biofilms. With the increasing development of antimicrobial resistance to traditional antibiotics, new technologies are needed to combat infections that cause human disease. Oral infections are rarely life threatening but have a significant impact on quality of life, economics, and oral and systemic health. The use of systemic antibiotics for the management of oral infections, especially in cases of the biofilm-associated diseases dental caries and periodontal disease, has not received considerable support because of the implications for the emergence of antibiotic resistance in medically important pathogens. However, the use of topical chemotherapeutic agents is gaining considerable support but the development of such agents is lagging behind the potential applications. We are evaluating the efficacy of natural and synthetic antimicrobial peptides against oral pathogens, grown both planktonically and in biofilms, in an attempt to develop new agents to fight oral infections.