title: Investigation into the Efficacy of Bdellovibrio bacteriovorus as a Novel Preharvest Intervention To Control Escherichia coli O157:H7 and Salmonella in Cattle Using an In Vitro Model.
abstract: Cattle are an important reservoir for the foodborne pathogens Salmonella and Escherichia coli O157:H7; they frequently harbor these microorganisms in their digestive tracts and shed them in their feces. Thus, there is potential for contamination of cattle hides and, subsequently, carcasses. Interventions aimed at reducing or eliminating pathogen shedding preharvest will also reduce the likelihood of beef product contamination by these pathogens. Therefore, this study used an in vitro model to evaluate Bdellovibrio bacteriovorus, a gram-negative microorganism that preys upon other gram-negative microorganisms, as a preharvest intervention to control Salmonella and E. coli O157:H7. Rumen fluid and feces were inoculated with pansusceptible or antimicrobial-resistant strains of one pathogen. Control samples were treated with HEPES buffer, whereas experimental samples were exposed to HEPES buffer plus B. bacteriovorus. Salmonella and E. coli O157:H7 populations were quantified at 0, 24, 48, and 72 h. The most-probable-number (MPN) technique, followed by streaking onto xylose lysine Tergitol 4 agar, was used to determine Salmonella populations, whereas spread plating onto sorbitol MacConkey agar supplemented with cefixime and tellurite was employed to enumerate E. coli O157:H7. B. bacteriovorus reduced pansusceptible Salmonella in cattle feces by 2.02 Log MPN/g (P = 0.0005) and antimicrobial-resistant Salmonella by 3.79 (P < 0.0001) and 2.24 (P = 0.0013) Log MPN/g after 24 and 48 h, respectively, in comparison to control samples. Significant reductions were not observed for E. coli O157:H7 in rumen or feces. These data suggest that further investigation into B. bacteriovorus efficacy as a preharvest intervention to control Salmonella in cattle is warranted.
authors: Department of Animal Sciences and Industry, Kansas State University, Olathe, Kansas 66061, USA.
authors: Jennifer A
authors: JA
authors: Page
authors: Kansas State Veterinary Diagnostic Laboratory, Kansas State University, Olathe, Kansas 66061, USA.
authors: Brian
authors: B
authors: Lubbers
authors: Kansas State Veterinary Diagnostic Laboratory, Kansas State University, Olathe, Kansas 66061, USA.
authors: Joshua
authors: J
authors: Maher
authors: Kansas State Veterinary Diagnostic Laboratory, Kansas State University, Olathe, Kansas 66061, USA.
authors: Linda
authors: L
authors: Ritsch
authors: Department of Animal Sciences and Industry, Kansas State University, Olathe, Kansas 66061, USA. saragragg@k-state.edu.
authors: Sara E
authors: SE
authors: Gragg
mesh_terms: D000818:Animals; D001501:Bdellovibrio / Q000254:growth & development / Q000302:isolation & purification*; D061046:Biological Control Agents; D002417:Cattle / Q000382:microbiology*; D019453:Escherichia coli O157 / Q000254:growth & development* / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology; D012417:Rumen / Q000382:microbiology; D012475:Salmonella / Q000254:growth & development / Q000302:isolation & purification
chemical_list: D061046:Biological Control Agents