Bielke L.R

Publications (2)0 Total impact

• Article: Selection and Application of Bacteriophages for Treating Salmonella enteritidis Infections in Poultry

  Higgins S.E, J.P. s Higgin, Bielke L.R, Hargis B.M
  [show abstract] [hide abstract]
  ABSTRACT: The objective of this study was to select appropriate bacteriophages that survive in the gastrointestinal tract of neonatal poultry and utilize those bacteriophages to reduce intestinal colonization of Salmonella enteritidis phage type 13A (SE) in challenged birds. Broiler chicks served as an in vivo biological filter to preferentially select bacteriophages from our bacteriophage library capable of surviving the gastrointestinal environment. A mixture of bacteriophage isolates designated PHL 1-71 was administered orally to three SE challenged chicks on three consecutive days. Each day, bacteriophages were recovered from the ileum, ileocecal junction and ceca for sequential administration the following day. The recovered bacteriophages were then administered to SE-infected turkey poults. In the first experiment, two-day old poults were challenged with 10⁴cfu SE and treated 48 h later with 5mM Mg (OH)₂ followed by 2.5×10⁹ plaque forming units (pfu) of bacteriophages in 1mM Mg (OH)₂ solution. This treatment numerically reduced SE recovered from cecal contents at 12 and 24 h after treatment as compared to untreated controls. In a second experiment, two-day old poults were challenged with 1.6×10⁴ cfu SE and treated with 5mM Mg (OH)₂ followed by 7.5×10⁹ pfu phage in 1mM Mg (OH)₂ solution 48 h post-challenge. We recovered 79,728 cfu of SE per g of cecal contents in the control group and 11,224 cfu/g in the phage treated group 24 h post treatment. These data were not significantly different, but they suggest that bacteriophages can be preferentially selected in vivo to increase survival in the avian gastrointestinal tract. However, improved efficacy is required prior to useful application of the approach for reducing Salmonella infection.
  International Journal of Poultry Science. 01/2007;
• Article: Effect of a Defined Competitive Exclusion Culture for Prophylaxis and Reduction of Horizontal Transmission of Salmonella enteritidis in Broiler Chickens

  Wolfenden A.D, Vicente J.L, Bielke L.R, Pixley C.M, Higgins S.E, Donoghue D.J, Donoghue A.M, Hargis B.M, Tellez G
  [show abstract] [hide abstract]
  ABSTRACT: Effective Competitive Exclusion (CE) cultures have been shown to accelerate development of normal microflora in chicks and poults, providing increased resistance to infection by some enteric bacterial pathogens. Our objective was to develop a CE culture for prophylaxis and reduced horizontal transmission of Salmonella enteritidis (SE) in broiler chickens. In the present study, seven members of the family Enterobacteriaceae and 2 lactic acid bacteria isolates, each capable of in vitro and in vivo inhibition of SE, were selected and combined to form the putative CE culture. In the first experiment, day-of-hatch chicks were randomly divided into four pens. All treated chicks were orally gavaged with the CE culture and 3 pens were treated with the CE culture in the drinking water for four consecutive days. Treated and control-non treated chicks were challenged with SE on day 4. All 3 groups of birds that were treated with the CE culture had a significant decrease (p<0.05) in cecal colonization compared with non-CE-treated SE-challenged chicks. Two additional experiments were designed to measure the efficacy of the CE culture in reducing SE horizontal transmission from infected to uninfected chicks when commingled. SE was recovered in the cecal tonsils with a significantly lower incidence at days 7 and 14 in Experiment 2 and day 7 in Experiment 3 from the groups that received the CE in the drinking water as compared to controls respectively. These results suggest that a relatively simple and defined CE culture can reduce SE colonization in neonatal chicks.
  International Journal of Poultry Science. 01/2007;