P-060. Relatedness of Bison and Bovine Fecal Isolates of Enterobacter sakazakii to Environmental, Clinical, and Food Isolates by Pulsed-field Gel Electrophoresis

T. A. Solseng, T. Johnson, H. Vinson, L. M. Nangoh, P. S. Gibbs;
North Dakota State Univ., Fargo, ND.

Enterobacter sakazakii is an opportunistic pathogen that is frequently associated with powdered infant formula. The organism causes necrotizing enteritis, sepsis and meningitis in infants that can result in death or mental illness. In adults, it can cause bacteremia, osteomyelitis, and vaginitis. Currently the reservoir for E. sakazakii has been elusive; and the epidemiology and pathogenicity are not well defined. E. sakazakii has been found to reside in the midgut of stable flies. Research in our laboratory at North Dakota State University has determined that E. sakazakii is present in bison and bovine feces, though it has not yet been proven that this is the primary source of E. sakazakii in powdered infant formula. Pulse-field gel electrophoresis was done to determine if the isolates from the bison and bovine feces were similar to other isolates found in food, clinical settings and the environment; these included ATCC strains, an isolate from a neonatal meningitis case, and multiple isolates of various origins received from Cornell University. There were 9-30 DNA fragments with a high degree of diversity among the isolates tested. Only the Cornell Isolates F6-049 and F6-051 had a high degree of similarity; both of these isolates were from a clinical source. Isolates from bison and bovine feces, 52 and N72, respectively, have a low degree of similarity to each other, 25%. Isolate 52 shows 65% similarity to an isolate from a food source, and N72 shows 55% similarity to an isolate from a clinical source. This study shows that some of the E. sakazakii isolates studied are closely related, but also that there is a high level of genetic diversity among the isolates based on the pulse-field gel electrophoresis.