WITHDRAWN: Streptococcus mutans inhibits the growth of Enterococcus via the non-ribosomal cyclic peptide mutanobactin

Area of Science:

• Microbiology
• Molecular Biology
• Biochemistry

Background:

• Enterococcus faecalis is an opportunistic pathogen causing nosocomial infections, complicated by antibiotic resistance.
• E. faecalis is linked to oral diseases and endodontic treatment failures, necessitating understanding its interactions within microbial communities.
• The interactions between E. faecalis and oral streptococci, crucial for microbiome establishment, are not well understood.

Purpose of the Study:

• To elucidate the mechanism by which Streptococcus mutans inhibits the growth of Enterococcus faecalis.
• To characterize the antimicrobial compound mutanobactin and its production system.
• To investigate the resistance mechanisms of E. faecalis against mutanobactin.

Main Methods:

• Identification and characterization of mutanobactin, a cyclic lipopeptide produced by S. mutans.
• Analysis of the polyketide synthase-nonribosomal peptide synthetase hybrid system (mub locus) responsible for mutanobactin production.
• Assessment of mutanobactin's activity against planktonic and biofilm growth of E. faecalis and other Gram-positive pathogens.
• Investigation of the role of E. faecalis virulence factor gelatinase in mutanobactin resistance.

Main Results:

• Streptococcus mutans produces mutanobactin, a cyclic lipopeptide that inhibits planktonic and biofilm growth of E. faecalis and other Gram-positive pathogens like Staphylococcus aureus.
• Mutanobactin damages the cell envelope of E. faecalis, similar to lipopeptide antibiotics such as daptomycin.
• Enterococcus faecalis resistance to mutanobactin is mediated by the secreted metalloprotease gelatinase.

Conclusions:

• Mutanobactin exhibits significant anti-biofilm potential, making it a promising natural product for therapeutic applications.
• This study provides insights into the complex interactions within polymicrobial communities, particularly between E. faecalis and oral streptococci.
• Understanding E. faecalis dynamics and resistance mechanisms in polymicrobial settings is crucial for managing infections and treatment failures.