Developing a Lung Tissue Bacterial Co-culture Model

Graduate #26
Discipline: Biological Sciences
Subcategory: Microbiology/Immunology/Virology

Shari Galvin - Texas Southern University

The three Gram negative bacteria belonging to the genus Yersinia that are pathogenic in humans are Yersinia enterocolitica, Yersinia pseudotuberculosis, and Yersinia pestis. The first two pathogens mentioned, infect the gut and cause self-limiting gastroenteritis. Y. pestis, in contrast, is the etiological agent of the bubonic, septicemic and pneumonic plague responsible for causing three major pandemics. The plague, which still exists in the modern world, is capable of killing infected patients within 3-7 days. Unless antibiotic treatment is started early, mortality rates can be as high as 66% and 93%. Previously, our group determined that exposure to indoor and outdoor dust impacted a number of opportunistic bacterial pathogens, mainly: Escherichia coli, Enterococcus faecalis (which are both gut flora) and Psuedomonas aeruginosa (found in gut and can cause pneumonic infection). While house dust enhanced bacterial growth in certain medium, both indoor and outdoor dust enhanced biofilm production of all three bacterial species, which could potentially alter their virulence potential. Dust, considered to be an environmental contaminant, becomes toxic when present in excess amounts either indoor or outdoor. Toxicity is attributed to composition of the dust contaminants. In furthering our previous studies, we sought to determine whether dust exposure could influence the proliferation of a bonafide pneumonic pathogen when cultured with lung tissue.

For this study we developed a lung tissue infection model system in which we determined the impact of dust on Y. pestis and its various isogenic mutant strains. To test this, bacterial co-culture with lung epithelial cells (A549) were challenged with various types of dust for a period of 6 hours. Bacterial loads were determined by plate counting. Future research will involve employing a murine pneumonic infection model system to further observe the impact of dust on aerosolized Y. pestis in addition to characterizing the impact of dust on Y. enterocolitica and Y. pseudotuberculosis in gut co-culture model systems.

ERNAbstractSG.docx

Funder Acknowledgement(s): This project was directly supported by the National Science Foundation Research Infrastructure in Science and Engineering (HRD 1345173).

Faculty Advisor: Jason A. Rosenzweig, rosenzweigja@tsu.edu