Campylobacter jejuniis a leading cause of bacterial gastroenteritis in the U.S., with an estimated cost of treatment and loss of productivity exceeding $1 billion annually. My lab is focused on the development of a vaccine to decreaseCampylobacter colonization in poultry. We are using an attenuatedSalmonella vector (from Dr. Roy Curtiss' lab at Arizona State University) to express Campylobacter antigens. Campylobacter is present as normal flora in the intestinal tract of broiler chickens, and thus a source of contamination in the human consumption of poultry. Prevention of Campylobacter within the chicken host through vaccination will contribute to a decrease of illnesses in humans. We are also examining Campylobacter in the cattle host in an epidemiological study that followed cattle beginning at the range, at the feedlot, at slaughter, and right through to the production of fine ground beef. Environmental samples including birds, flies, feed, feed bunks, watering units, and floor of the pens were also examined for Campylobacter. Currently, we are conducting macrorestriction profile - pulsed field gel electrophoresis (MRP-PFGE) on the various Campylobacter isolates to search for associations between genotypes and hosts.
Salmonella Newport
Research in Salmonella Newport focuses on the emergence in oysters of a particular genotype of S. Newport, matching pattern JJPX01.0014 in PulseNet. Our previous study detected S. Newport in 12 of 36 bays, with an overall prevalence level of 7.4% in oyster meat. S. Newport is of particular interest, because it is currently ranked as the 3rd most commonly reported Salmonella serotype by the CDC. JJPX01.0014 is a pattern commonly found in bovine isolates and thus, being prevalent in oysters is indicative of agricultural runoff into oyster-rearing waters. S. Newport JJXP01.0014 is also the first multi-drug resistant (MDR) AmpC pattern identified by PulseNet, signifying resistance to at least 9 antimicrobials. It has been persistent in CDC's database since 1999 and isolated from outbreaks in 39 states and Canada. Research being conducted involves understanding how and why this one genotype is prevalent in oysters and includes survival studies in oysters comparing various genotypes in various conditions, immuno-histochemistry and histopathological examination of oyster tissue, depuration studies, vertical transmission studies, prevalence studies, transposon site hybridization (TraSH) analysis to determine genes involved, and producing and testing mutants for survival in oysters.
Selected Publications
Brillhart, C.D., L.A. Joens. Prevalence and characterization of Salmonella serovars isolated from oysters served raw in restaurants. J Food Prot. 74(6):1025-9. 2011.
Morrison, C.M., Armstrong, A.E., Evans, S., Mild, R.M., Langdon, C.J., L.A. Joens. Survival of Salmonella Newport in oysters. Int J Food Microbiol. Epub May 13. 2011.
Mild, R.M., L.A. Joens, Friedman, M., Olsen, C.W., McHugh, T.H., Law, B., Ravishankar S. Antimicrobial edible apple films inactivate antibiotic resistant and susceptible Campylobacter jejuni strains on chicken breast. J Food Sci. 76(3):M163-8. 2011.
Cooper, K.K., Cooper, M.A., Zuccolo, A., Law, B., L.A. Joens. Complete Genome Sequence of Campylobacter jejuni Strain S3. J Bacteriol. 193(6):1491-2. Epub Jan7. 2011.
Ravishankar S., Zhu, L., Reyna-Grenados, J., Law, B., L.A. Joens, Friedman, M. Carvacrol and cinnamaldehyde inactivate antibiotic-resistant Salmonella enterica in buffer and on celery and oysters. J Food Prot. 73 (2):234-40. 2010.
