Commensal Oral Rothia mucilaginosa Produces Enterobactin, a Metal-Chelating Siderophore

Area of Science:

• Microbiology
• Biochemistry

Background:

• Rothia species are ubiquitous in the human oral microbiota.
• The chemical ecology of Rothia bacteria is largely unexplored.
• Biosynthetic gene clusters (BGCs) encode specialized small molecules involved in microbial interactions.

Purpose of the Study:

• To investigate the molecular mechanisms of Rothia's chemical ecology.
• To identify novel small molecules produced by Rothia species.
• To understand the role of these molecules in oral microbial community dynamics.

Main Methods:

• Genome mining for BGCs in 45 Rothia genomes.
• Culturing R. mucilaginosa and analyzing metabolites using LC-MS/MS, HPLC, and NMR.
• Cocultivation experiments with oral bacteria and purified enterobactin.

Main Results:

• A catechol-siderophore-like BGC was identified in all studied Rothia genomes.
• Enterobactin was identified as a siderophore produced by R. mucilaginosa.
• Enterobactin inhibited the growth of cariogenic Streptococcus mutans and pathogenic Staphylococcus aureus.
• Effects on other commensal oral bacteria varied, including growth inhibition or induction.

Conclusions:

• R. mucilaginosa produces enterobactin, a siderophore typically found in gut pathogens.
• Enterobactin production contributes to R. mucilaginosa's prevalence in the oral cavity.
• The iron-scavenging role of enterobactin in oral health warrants further investigation.