Antimicrobial Activity of Lactic Acid Bacteria Starters against Acid Tolerant, Antibiotic Resistant, and Potentially VirulentE. coliIsolated from a Fermented Sorghum-Millet Beverage

Abstract

Bacterial contamination of fermented foods is a serious global food safety challenge that requires effective control strategies. This study characterized presumptiveE. coliisolated fromObushera, a traditional fermented cereal beverage from Uganda. Thereafter, the antimicrobial effect of lactic acid bacteria (LAB) previously isolated fromObushera,against theE. coli, was examined. The presumptiveE. coliwas incubated in brain heart infusion broth (pH = 3.6) at 25°C for 48 h. The most acid-stable strains were clustered using (GTG)5rep-PCR fingerprinting and identified using 16S rRNA sequencing.E. coliwas screened forShigatoxins (Stx 1andStx 2) andIntimin(eae) virulence genes as well as antibiotic resistance. The spot-on-the-lawn method was used to evaluate antimicrobial activity. Eighteen isolates were acid stable and are identified asE. coli,Shigella, andLysinibacillus.TheStx2 gene and antibiotic resistance were detected in someE.coliisolates. The LAB were antagonistic against theE. coli. Lactic acid bacteria from traditional fermented foods can be applied in food processing to inhibit pathogens.Obusheralactic acid bacteria could be used to improve the safety of fermented foods.