Environmental Distribution and Disease Potential of New Legionella-like Bacteria As a Function of Environmental VariablesEPA Grant Number: R827111
Title: Environmental Distribution and Disease Potential of New Legionella-like Bacteria As a Function of Environmental Variables
Investigators: Berk, Sharon G. , Farone, Anthony L. , Gunderson, John H. , Newsome, Anthony L. , Uddin, Nazim
Institution: Tennessee Technological University , Middle Tennessee State University
EPA Project Officer: Hahn, Intaek
Project Period: December 1, 1998 through November 30, 2001 (Extended to November 30, 2002)
Project Amount: $396,060
RFA: Exploratory Research - Environmental Biology (1998) RFA Text | Recipients Lists
Research Category: Health , Ecosystems , Biology/Life Sciences
Bacteria parasitic in amoebae may be an unrecognized significant cause of respiratory disease. The bacteria are closely related to Legionella species and have been termed "Legionella-like amoebal pathogens" (LLAPs). Most do not grow on media used for routine monitoring. About 12 LLAPs have been isolated in England. Recently one has been isolated from soil in Tennessee. Its rRNA sequence reveals a close relationship to other Legionella species. LLAPs are perhaps new species of Legionella which may cause disease but are not detected by routine analyses. This proposal aims to conduct a search for new LLAPs in natural and man-made environments, and to find any correlations between LLAP occurrence and environmental parameters.
The study involves four areas of expertise: environmental, molecular/phylogenetic, clinical/immunological and statistical. Temperature, pH, nitrogen, dissolved organic carbon, and total bacterial counts will be measured for all aquatic habitats; and logistic regression analyses will be used to determine variables which predict the distribution of LLAPs in the environment. Isolates will be obtained from infected amoebae in environmental samples. Monolayers of axenic lab-cultured amoebae will be inoculated with aliquots of infected amoebae. Isolates will be characterized by histochemical stains, rRNA sequences and phylogenetic analyses. Potential for human disease will be examined by infectivity studies using U937 (macrophage-like) cell lines.
This work should reveal the prevalence of the new potential human pathogens, and it should predict environments likely to have a high incidence of the bacteria. The study will also provide a battery of LLAPs for future screening of serum from patients suffering from pneumonia of unknown etiology.
Improvements in Risk Assessment or Risk Management: Results may lead to development of gene probes for identifying LLAPs in environmental samples, which could aid in risk assessment. Enhancement of detection by enrichment of samples via amoebal infection would also improve detection of viable pathogens for risk assessment.