During the course of my educational and work-related activities, I have had the opportunities for research activities in several areas of bacteriology and parasitology. Much of my early work was directed at pathogenic free-living amoebae. This led to studies with Legionella pneumophilia and its interactions with amoebae. I continue to have interests in this area and recent studies have been directed at the amoeba Entamoeba gingivalis. I have also investigated the antibacterial properties of human lactoferrin (a protein in human secretions). Recent studies at MTSU have also suggested it can influence enzyme activity through metal chelation. In recent years, I have also investigated the natural history and disease potential in Tennessee of the pathogenic protozoa Trypanosoma cruzi. Since 2002 and continuing to the present, I have investigated the antibacterial properties and potential novel applications for uses of chlorine dioxide. These investigations are made possible with the availability of a newly developed highly portable chlorine dioxide generation system.

Co-investigator on grants from the Environmental Protection Agency entitled "Protozoa in Risk Assessment of Legionellosis - Inadequacy of Guidelines and Monitoring," funded for three years beginning October 1996, and Environmental Distribution and Disease Potential of New Legionella-like Bacteria As A Function of Environmental Variables 1998-2002.

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Chlorine dioxide

Chlorine dioxide has a long history of use as a disinfectant for use in treatment of potable water and in the food preparation industry. It was also used to decontaminate federal buildings following the intentional release of anthrax in the United States in 2001. The more widespread use of chlorine dioxide gas, however, has been hampered since the gas is too unstable to be shipped and it must be prepared at the use site. Historically, this has also required the need for dedicated gas generation equipment and personnel training. . It is now feasible to easily produce the gas for local use with a minimum of material needs and personnel training. One system (ICA TriNova, Newnan, GA.) consists of an impregnate within a sachet that is gas permeable. It can produce ClO2 gas or be submerged in water creating a ClO2 solution. Our aim has been to demonstrate use of this system in novel disinfection applications to reduce human exposure to infectious bacteria such as methicillin-resistantStaphylococcus aureus (MRSA), Listeria monocytogenes, and inactivate bacteria spores. Research has gained interest from groups as diverse as the Tennessee Department of Health and Homeland Security to sports equipment managers and first responders. The potential emergence of resistant bacteria forms and the exact mechanism by which bacteria may be inactivated by chlorine dioxide remains to be clearly defined. Future studies will likely address these issues.

Parasitic protozoa

Trypanosoma cruzi (the etiological agent of Chagas, disease) is a major cause of human illness in Central and South America. In 2000 the occurrence of this parasite in Tennessee was first reported in a local insect vector, local wildlife, and a native resident of middle Tennessee. Subsequent and current studies are directed at identifying the distribution, occurrence, and disease potential in native Tennessee insects, wildlife, domestic canines, and humans.

Investigators using light microscopy have identified the protozoan parasite Entamoeba gingivalis from human diseased gingival pockets for nearly 100 years. An objective here was to develop a molecular biology approach for determining the presence of E. gingivalis in both diseased gingival pockets and healthy gingival sites. For real-time PCR development, a primer set was designed to amplify a 135-bp fragment inside the SSU rDNA of E. gingivalis. Amoebae were detected only within diseased gingival pockets. The newly described methodology may serve to provide a novel eukaryotic cell marker of disease status in human gingival pockets.

New anti-protozoan drugs are urgently needed to treat and control diseases such as sleeping sickness, Chagas' disease, leishmaniasis, and Cryptosporidium infections. Current graduate students under my direction are planning to incorporate in vivo high-throughput assays to assess botanical extracts for novel anti-parasitic pharmaceutical agents.

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