Lactic acid bacteria (LAB), a type of probiotic bacteria, have been previously shown to possess an outstanding capacity to bind and remove heavy metal ions through mechanisms like complexation, chelation, or biosorption, utilizing their secreted extracellular polymeric substances. This study reports the whole genome sequence analysis of a LAB strain, Enterococcus durans E1T1, previously isolated from infant faeces. This bacterium exhibits tolerance to high concentrations of heavy metals (Cd, Pb, Hg, Fe, and Cr(VI)) and displays notable auto- and co-aggregation capabilities, along with significant exopolysaccharide production. The annotation process revealed that the E1T1 genome has a total length of 2 970 567 bp, a GC content of 37.8%, and various subsystem features. A total of 2836 coding sequences were assigned recognized functions. Analysis determined that strain E1T1 contains gene clusters such as czc and mer, which encode different heavy metal resistance mechanisms vital for survival under strict conditions. Genomic analysis also predicted two bile salt hydrolases, apparently critical for gastrointestinal tract (GIT) survival, genes encoding multidrug resistance efflux pumps, and fluoroquinolone resistance genes, potentially conferring high antibiotic resistance to strain E1T1.
Abbas et al. (Sun,) studied this question.