Beneficial Properties of Enterococcus faecium Strains Isolated From Bats' Fecal Samples

Area of Science:

• Microbiology
• Probiotics
• Food Safety

Background:

• Enterococcus faecium (E. faecium) is a common bacterium with known probiotic and pathogenic potential.
• Bats, specifically Nyctalus noctula, are increasingly recognized as potential reservoirs for novel microorganisms.

Purpose of the Study:

• To isolate and characterize E. faecium from Nyctalus noctula bat feces.
• To evaluate the probiotic potential and antimicrobial properties of isolated E. faecium strains.
• To assess the safety and potential applications of these strains in food safety and gut health.

Main Methods:

• Fecal sample collection from Nyctalus noctula bats.
• Screening for antimicrobial activity against Listeria monocytogenes.
• Bacterial identification using rep-PCR fingerprinting and 16S rRNA sequencing.
• Confirmation of bacteriocin production and stability testing (pH, temperature, chemical conditions).
• Assessment of probiotic traits (hydrophobicity, enzymatic activity) and virulence factors (hemolytic, mucin degradation activity).
• Molecular analysis for bacteriocin and GABA synthesis genes.

Main Results:

• Two bacteriocin-producing E. faecium strains (ST01TL and ST76TL) were isolated.
• Antimicrobial substances were proteinaceous, stable across various conditions, and effective against Listeria monocytogenes.
• Strains exhibited desirable probiotic traits like hydrophobicity and beneficial enzymatic activity, with no hemolytic or mucin degradation.
• Genes for bacteriocin and GABA synthesis were detected.
• Limited virulence traits and antibiotic resistance profiles were identified, necessitating further investigation.

Conclusions:

• E. faecium strains from Nyctalus noctula bats possess significant probiotic potential and stable antimicrobial activity.
• These strains could be valuable for food safety applications and gut health improvement.
• Bats represent a novel source for probiotic discovery, but comprehensive safety evaluations including whole genome sequencing are essential before application.