Mechanism of Action of <i>Streptococcus downii</i>, a New Bacterial Species with Probiotic Potential

• Main Authors: Lucía Martínez-Lamas (Author), Eliane García-Mato (Author), Anniris Rincón-Quintero (Author), Berta Rivas-Mundiña (Author), Pedro Diz-Dios (Author), Maximiliano Álvarez-Fernández (Author)
• Format: Book
• Published: MDPI AG, 2023-09-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.

Summary

<i>Streptococcus downii</i> is a recently reported bacterial species of oral origin, with inhibitory capacity against <i>Streptococcus mutans</i>, <i>Actinomyces naeslundii</i>, <i>Veillonella parvula</i> and <i>Aggregatibacter actinomycetemcomitans</i>, which confers upon it the potential of being an oral probiotic. The aim of the present study was to identify the potential mechanisms by which <i>S. downii</i> exerts its inhibitory effect on <i>S. mutans</i>. To this end, the study assessed the consumption of glucose and proteins available in the culture medium, the modification of the pH, the production of short-chain fatty acids, the changes in the protein panel of the inhibition halo, the production of hydrogen peroxide and the effect of proteinase K. There were no differences in the glucose values or in the protein content of the medium, but there was a reduction in pH (with no effect on the growth of <i>S. mutans</i>). Significant increases were detected in the levels of lactic and formic acid (with no effect on the growth of <i>S. mutans</i>), as well as changes in the peptide panel (with no effect on the growth of <i>S. mutans</i>). The inhibitory effect was maintained in the presence of peroxidase but disappeared after adding proteinase K. Based on these results, it is suggested that the main mechanism of inhibition of <i>S. downii</i> against <i>S. mutans</i> is the production of bacteriocins.

Item Description

10.3390/antibiotics12091472
2079-6382