Efficacies of Thai probiotic strains against antibiotic resistance bacteria and modulate gut microbiome and resistome in pig model

Abstract

Lactic acid bacteria (LAB) have been widely used as probiotics in the livestock industry because of their high potential for antibacterial activity, anticonjugation, antibiofilm capacity, and gut microbiome regulation. Lactobacillus plantarum 22F, 25F (L22F and L25F), and Pediococcus acidilactici 72N (P72N) showed several promising in vitro and in vivo properties, according to our recent research. The objective of this study was to evaluate the Thai LAB efficacy on anticonjugation and antibiofilm activities in E. coli harboring the mcr-1 gene. When compared to the neutralizing cell-free supernatant (CFS), we discovered that the CFS derived from our LAB strains at 1:16 dilution (pH 5.70-5.92) significantly reduced the transfer frequency of the mcr-1 gene between the donor and recipient E. coli by up to 100 times (pH 6.5). Furthermore, our non-neutralizing CFS has the potential to significantly reduce the production of E. coli biofilm by more than 82 % for planktonic biofilm and 60 % for sessile biofilm, respectively. It has the potential to inhibit biofilm development in the planktonic stage by up to 52 % when used to neutralize CFS. The effect of our LAB on the gut microbiota and resistome in weaned piglets with and without enterotoxigenic Escherichia coli (ETEC) infection was monitored and observed using whole-genome shotgun metagenomics. The findings revealed that a multi-strain LAB containing L22F, L25F, and P72N could help to expand beneficial bacteria families such as Lactobacillaceae, Lachnospiraceae, and Ruminococcaceae. In comparison to antibiotic pigs, it also lowered beta-lactam resistance, copper resistance, multi-biocide resistance, tetW, and tetQ. In piglets treated with our LAB strains, IncX4, a plasmid associated with colistin resistance, was reduced, and an integrase gene (intI) class 2 and 3 could not be detected. However, this group was also enriched in the insertion sequences (IS) 3 and 30, which are linked to nutrition use. Furthermore, in LAB supplemented piglets, the detoxification and oxidative stress response, which is connected to antioxidant activity, as well as amino acid and glucose metabolism, were all boosted. Our findings may highlight the LAB properties inhibiting antimicrobial resistance bacteria, positively affecting gut microbiome, and resistome modulation based on metagenomic research.