Physiological and Structural Differences Between Enterococcus faecalis JH2-2 and Mutant Strains Resistant to...

Area of Science:

• Microbiology
• Bacteriocin Research
• Molecular Biology

Background:

• Enterococcus faecalis strains can develop resistance to bacteriocins, which are antimicrobial peptides.
• Divercin RV41 (DvnRV41) is a subclass IIa bacteriocin produced by Escherichia coli.
• Understanding resistance mechanisms is crucial for bacteriocin applications.

Purpose of the Study:

• To investigate physiological and structural differences between wild-type Enterococcus faecalis JH2-2 and three DvnRV41-resistant mutant strains.
• To characterize the resistance profiles of mutants 35A1, 35H1, and 36H4 against lysozyme and DvnRV41.

Main Methods:

• Isolation and characterization of three Enterococcus faecalis mutant strains with intermediate resistance to recombinant DvnRV41.
• Assessment of bacterial growth and resistance to lysozyme.
• Fourier transform infrared spectroscopy (FT-IR) for structural analysis.

Main Results:

• No cross-resistance was observed between lysozyme and DvnRV41; an additive effect was noted with combined treatment.
• FT-IR analysis revealed significant structural differences in mutants 35H1 and 36H4 compared to the wild-type and mutant 35A1.
• These structural variations were primarily associated with changes in fatty acid composition and polysaccharide content.

Conclusions:

• Mutations affecting phosphoesterase activity, σ54 factor, and glycerophosphodiesterase influence Enterococcus faecalis structure and DvnRV41 resistance.
• FT-IR is a valuable tool for detecting subtle structural alterations in bacteria related to bacteriocin resistance.
• This study enhances the understanding of Enterococcus faecalis sensitivity and resistance mechanisms to subclass IIa bacteriocins like DvnRV41.