Bacterial communication between Lactobacillus spp. isolated from poultry in the inhibition of Salmonella Heidelberg—proof of concept

Abstract

Bacterial communication has become an increasingly studied topic aiming at the discovery of new products to aid the treatment of diseases for which conventional options do not work. The production of safe foods, free of pathogens, has been receiving increasing attention due to market demands for food products of high quality and free of residues. This study assessed the communication between Lactobacillus spp. during the in vitro inhibition of Salmonella Heidelberg (SH) and the impact an autoinducer produced by a strain of Lactobacillus plantarum has on communication in the normal microbiota and inhibiting SH in newborn chicks. For this purpose, the isolates of Lactobacillus spp. were isolated cloacal swabs of broilers and identified through biochemical and molecular assays and were obtained from broiler farms. They later had their inhibitory potential against SH stimulated after contact with the autoinducer. For assessing bacterial communication (quorum sensing) during the inhibition of SH by Lactobacillus spp., a spot on the lawn assay was conducted. For the in vivo, 75 one-day-old chicks were divided in 5 experimental groups: control with no treatment; treatment with a Lactobacillus spp. pool on the first day; treatment with autoinducer on the second day; treatment with Lactobacillus spp. on the first day; and autoinducer on the second day and treatment without autoinducer. The autoinducer was assessed through an SH count in the ceca of the birds. The autoinducer produced by the strain of L. plantarum proved to be efficient for communicating with the other Lactobacillus spp. isolates as previous contact with SH induced the production of an autoinducer capable of increasing inhibition of SH both in vitro (in average 132.73%) and in vivo, acting similarly to the Lactobacillus spp. pool (probiotic) by decreasing the SH count in the ceca (64%-24 h, 42%-96 h, and 46%-168 h).

Probiotic Lactobacilli Do Not Protect Chickens against Salmonella Enteritidis Infection by Competitive Exclusion in the Intestinal Tract but in Feed, Outside the Chicken Host

“…It has been repeatedly confirmed that lactobacilli produce metabolites that suppress the growth of Salmonella [28][29][30]. Lactobacilli also produce metabolites affecting host gene expression [31,32].…”

Advances in enteropathogen control throughout the meat chicken production chain

“…While potentially less practical, probiotics can also be delivered to chicks orally shortly after hatch. A number of studies found that single oral doses of probiotics on day 0 or 1 of life can protect against Salmonella early in life, leading to reductions in Salmonella prevalence in the spleen and liver (Yang et al., 2014) and ceca (Higgins et al., 2010; Marietto‐Goncalves et al., 2014; Schneitz et al., 2016; Sornplang et al., 2015; Telg & Caldwell, 2009; Waewdee et al., 2012), and reducing cecal counts by 0.9–3 log 10 CFU/g (Menconi et al., 2011; Nakphaichit et al., 2019; Okamoto et al., 2018; Prado‐Rebolledo et al., 2017; Revolledo et al., 2009; Telg & Caldwell, 2009). Treatments consisting of multiple oral doses of a Lactobacillus probiotic starting from day 1 of life were also found to reduce cecal Salmonella (Chen et al., 2012; Olnood et al., 2015).…”

Advances in Enteropathogen Control Throughout the Meat Chicken Production Chain

“…A number of studies found that single oral doses of probiotics on days 0 or 1 of life can protect against Salmonella early in life, where they led to reductions in Salmonella prevalence in the spleen and liver [38] and ceca [39][40][41][42][43], and reduced cecal counts by 0.9-3 log10 CFU/g [43][44][45][46][47]. Treatments consisting of multiple oral doses of a Lactobacillus probiotic starting from day 1 of life were found to reduce cecal Salmonella [48,49].…”