title: Production of organic acids by probiotic lactobacilli can be used to reduce pathogen load in poultry.
abstract: Probiotic Lactobacillus can be used to reduce the colonization of pathogenic bacteria in food animals, and therefore reduce the risk of foodborne illness to consumers. As a model system, we examined the mechanism of protection conferred by Lactobacillus species to inhibit C. jejuni growth in vitro and reduce colonization in broiler chickens. Possible mechanisms for the reduction of pathogens by lactobacilli include: 1) stimulation of adaptive immunity; 2) alteration of the cecal microbiome; and, 3) production of inhibitory metabolites, such as organic acids. The Lactobacillus species produced lactic acid at concentrations sufficient to kill C. jejuni in vitro. We determined that lactic acid produced by Lactobacillus disrupted the membrane of C. jejuni, as judged by biophotonics. The spectral features obtained using Fourier-transform infrared (FT-IR) and Raman spectroscopy techniques were used to accurately predict bacterial viability and differentiate C. jejuni samples according to lactic acid treatment. FT-IR spectral features of C. jejuni and Lactobacillus grown in co-culture revealed that the metabolism was dominated by Lactobacillus prior to the killing of C. jejuni. Based on our results, the development of future competitive exclusion strategies should include the evaluation of organic acid production.
authors.affiliation: School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America.
authors.forename: Jason M
authors.initials: JM
authors.lastname: Neal-McKinney
authors.forename: Xiaonan
authors.initials: X
authors.lastname: Lu
authors.forename: Tri
authors.initials: T
authors.lastname: Duong
authors.forename: Charles L
authors.initials: CL
authors.lastname: Larson
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Call
authors.forename: Devendra H
authors.initials: DH
authors.lastname: Shah
authors.forename: Michael E
authors.initials: ME
authors.lastname: Konkel
mesh_terms: D000284:Administration, Oral; D000818:Animals; D058491:Bacterial Load / Q000187:drug effects; D002169:Campylobacter Infections / Q000382:microbiology / Q000517:prevention & control* / Q000662:veterinary*; D016123:Campylobacter jejuni / Q000187:drug effects / Q000254:growth & development; D002645:Chickens / Q000382:microbiology*; D018920:Coculture Techniques; D019344:Lactic Acid / Q000096:biosynthesis / Q000494:pharmacology; D007778:Lactobacillus / Q000378:metabolism*; D050296:Microbial Viability / Q000187:drug effects; D011201:Poultry Diseases / Q000382:microbiology / Q000517:prevention & control*; D019936:Probiotics / Q000008:administration & dosage* / Q000627:therapeutic use; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman
chemical_list: D019344:Lactic Acid