Lactobacillus bulgaricus, Lactobacillus rhamnosus and Lactobacillus paracasei Attenuate Salmonella Enteritidis, Salmonella Heidelberg and Salmonella Typhimurium Colonization and Virulence Gene Expression In Vitro

Abstract

<i>Salmonella</i> Enteritidis (SE), <i>Salmonella</i> Typhimurium (ST), and <i>Salmonella</i> Heidelberg (SH) have been responsible for numerous outbreaks associated with the consumption of poultry meat and eggs. <i>Salmonella</i> colonization in chicken is characterized by initial attachment to the cecal epithelial cells (CEC) followed by dissemination to the liver, spleen, and oviduct. Since cecal colonization is critical to <i>Salmonella</i> transmission along the food chain continuum, reducing this intestinal association could potentially decrease poultry meat and egg contamination. Hence, this study investigated the efficacy of <i>Lactobacillus delbreuckii</i> sub species <i>bulgaricus</i> (NRRL B548; LD), <i>Lactobacillus paracasei</i> (DUP-13076; LP), and <i>Lactobacillus rhamnosus</i> (NRRL B442; LR) in reducing SE, ST, and SH colonization in CEC and survival in chicken macrophages. Additionally, their effect on expression of <i>Salmonella</i> virulence genes essential for cecal colonization and survival in macrophages was evaluated. All three probiotics significantly reduced <i>Salmonella</i> adhesion and invasion in CEC and survival in chicken macrophages (<i>p</i> < 0.05). Further, the probiotic treatment led to a significant reduction in <i>Salmonella</i> virulence gene expression (<i>p</i> < 0.05). Results of the study indicate that LD, LP, and LR could potentially be used to control SE, ST, and SH colonization in chicken. However, these observations warrant further in vivo validation.