Modulatory effects of Lactococcus lactis on gut microbiota of albino rats induced with Escherichia coli O175:H7

Abstract

The human microbiome, comprises of diverse microbial communities, is crucial for maintaining human health, especially within the gut. Escherichia coli O157:H7, known for its Shiga toxin production, is a major cause of diarrhea. Lactic acid bacteria (LAB) are recognized for their potential in preventing E. coli O157:H7 infection. This study aimed to assess the impact of LAB treatment on the intestinal microbiota of Albino rats infected with E. coli O157:H7. Experimental Albino rats were induced with Escherichia coli and diarrhea set in after three days and treated with Lactococcus lactis as probiotics, compared to a control group. Stool samples underwent 16S metagenomic profiling using the Pacbio platform. Results showed a bacterial dominance in the Kingdom domain, with increased read counts post-treatment. Phylum-level analysis revealed dominance by Proteobacteria, Firmicutes, Actinobacteria, Cyanobacteria, and Bacteroidetes. Approximately half of the identified taxa were novel "Phylotypes." Predominant species/phylotypes included Pediococcus acidilacticci, Pediococcus, Collinsella aerofaciens, and Lactobacillus. While some organisms decreased post-treatment, new commensals and symbionts were acquired. This study highlights significant differences in the intestinal microbiota of Albino rats pre- and post-LAB treatment, indicating L. lactis' efficacy in alleviating E. coli O157:H7-induced diarrhea and enriching gut microbiota.