Selected Publications   Davies, M., J. Engel, D. Griffin, D. Ginzl, R. Hopkins, C. Blackmore, E. Lawaczec, L. Nathan, C. Levy, G. Briggs, C. Kioski, S. Kreis, J. Keen, L. Durso, J. Schulte, K. Fullerton, C. Long, S. Smith, C. Barton, C. Gleit, M. Joyner, S. Montgomery, C. Braden, B. Goode, D. Chertow, C. O’Reilly, S. Gupta, and J. Dunn.  2005.  Outbreaks of Escherichia coli O157:H7 associated with petting zoos – North Carolina, Florida, and Arizona, 2004 and 2005.  Morb. Mortal. Wkly Rpt. 54(50):1277-1280.   Durso, L. M., J. L. Bono, and J. E. Keen.  2005.  Molecular serotyping of Escherichia coli O26:H11.  Appl. Environ. Microbiol. 71(8):4941-4944.   Durso, L. M., K. Reynolds, N. Bauer, Jr., and J. E. Keen.  2005.  Shiga-toxigenic Escherichia coli O157:H7 infections among livestock exhibitors and visitors at a Texas county fair.  Vector-Borne and Zoonotic Dis. 5(2):193-201.

I am interested in issues of applied food safety and microbial ecology.  My current research focuses on shiga-toxigenic Escherichia coli (STEC), including E. coli O157:H7 – an important food borne pathogen that can cause bloody diarrhea, hemolytic uremic syndrome, and sometimes death.  The main vehicle for this pathogen is thought to be foods of cattle origin.  However, despite intense research efforts aimed at controlling and eliminating E. coli O157:H7, little is known about the means by which this organism spreads and persists in foods and the food production environment, including its tenure in the cattle host and its survival outsides of humans and cattle.  It is also not understood what physiological properties, if any, distinguish these pathogens from their harmless commensal counterparts that live as normal members of the human and bovine gastrointestinal tracts.  The resources available at USMARC provide an outstanding opportunity to pursue these questions in applied animal production environments.

 One of my projects involves development of methods to characterize non-O157 STEC collected and isolated from pre-harvest animals and their environments.  I have produced a “molecular serotyping” assay for STEC O26:H11.  In traditional serotyping we look at a specific protein that is found on the outside of the bacteria.  All proteins are coded for by DNA.  In my assay, we look at the DNA directly.  This assay has been thoroughly evaluated and it works just as good as the traditional serotyping, but takes less time, eliminates the need for animal-derived reagents, and costs less to run.

A second project involves the microbial ecology of STEC both within and outside of the cattle gastrointestinal tract.  The premise for this research is that STEC are only one member of a livestock production-associated microbial community, and that the development of long-term strategies to control or eliminate these important food borne pathogens depends on understanding the organism throughout the entirety of its lifecycle.

Finally, my work at USMARC also includes collaborating on projects involved with the epidemiology of STEC in fair animals and the role of flies as vectors or markers of STEC in cattle production settings.