Inhibitory Effects of the Spore-forming Bacillus spp. on the Expression Levels of eae, luxS, flu, and ctxM Genes in E. coli Isolates

Abstract

Background Escherichia coli antibiotic resistance is one of the major health problems in many countries. Nowadays, researchers are focusing on novel approaches for the treatment of E. coli infections, including the use of spore-forming probiotics for their high stability in the harsh gastrointestinal (GIT) environment.MethodsInitially, 300 stool samples were collected from patients with gastrointestinal infections admitted to Imam Khomeini Hospital in Tehran. Then, diagnostic tests were performed to detect E. coli isolates on the samples. A DNA test was applied to examine the presence of ctxM, luxS, eae and flu in the samples. Afterward, the effect of native and commercial probiotics of Bacillus subtilis and Bacillus coagulant was investigated on the expression of the studied genes. ResultsGenes of flu, eae, luxS, and ctxM which are involved in bacterial attachment, biofilm formation, signaling, and antimicrobial resistance were existing in four out of 40 E. coli isolated among patients suffering from diarrhea. The expression levels of flu, luxS, eae, and ctxM genes decreased significantly (p-value < 0.05) after co-culture of E. coli with B. subtilis ATCC 6633 and broiler-derived B. subtilis. Both broiler-derived B. subtilis and broiler-derived B. coagulans have a significant effect on all the studied genes.Conclusions The broiler-derived isolates had a greater capacity to decrease the expression of these genes than the standard strains, proposing their adoption for dietary supplementations.