In Vitro Anti-Biofilm and Antibacterial Properties of Streptococcus downii sp. nov.

Abstract

The aim of this study was to evaluate the potential anti-biofilm and antibacterial activities of Streptococcus downii sp. nov. To test anti-biofilm properties, Streptococcus mutans, Actinomyces naeslundii, Veillonella parvula, Fusobacterium nucleatum, Porphyromonas gingivalis, and Aggregatibacter actinomycetemcomitans were grown in a biofilm model in the presence or not of S. downii sp. nov. for up to 120 h. For the potential antibacterial activity, 24 h-biofilms were exposed to S. downii sp. nov for 24 and 48 h. Biofilms structures and bacterial viability were studied by microscopy, and the effect in bacterial load by quantitative polymerase chain reaction. A generalized linear model was constructed, and results were considered as statistically significant at p < 0.05. The presence of S. downii sp. nov. during biofilm development did not affect the structure of the community, but an anti-biofilm effect against S. mutans was observed (p < 0.001, after 96 and 120 h). For antibacterial activity, after 24 h of exposure to S. downii sp. nov., counts of S. mutans (p = 0.019) and A. actinomycetemcomitans (p = 0.020) were significantly reduced in well-structured biofilms. Although moderate, anti-biofilm and antibacterial activities of S. downii sp. nov. against oral bacteria, including some periodontal pathogens, were demonstrated in an in vitro biofilm model.

Molecular Detection of Streptococcus downii sp. nov. from Dental Plaque Samples from Patients with Down Syndrome and Non-Syndromic Individuals

“…Accordingly, there has been growing interest in a number of alternative strategies to antibiotics in the dental setting, strategies that do not share the adverse effects of antibiotics, such as antimicrobial photodynamic therapy [54] and the use of probiotics to re-establish oral homeostasis [55]. The interest in detecting S. downii lies in its antibacterial activity against a number of cariogenic species and certain periodontal pathogens [17,18], which makes S. downii a potential probiotic. [PubMed]…”

“…S. downii is an alpha-hemolytic, Gram-positive coccus that differs biochemically from the closely related Streptococcus species due to the production of α-galactosidase, β-galactosidase and N-acetyl-β-D-glucosaminidase, and by the absence of arginine dihydrolasedesiminase and IgA1 protease. The most attractive characteristic of S. downii due to its potential for preserving oral health is that it inhibits the growth of S. mutans and certain periodontal pathogens such as Aggregatibacter actinomycetemcomitans, both in plaque growth [17] and in an in vitro biofilm model [18]. Although its mechanism of action has not been definitively clarified, the genomic analysis of S. downii has revealed the presence of putative genes of the family of bacteriocin IIb lactobinA/cerein 7B (data not shown).…”

Oral Biofilm Cryotherapy as a Novel Ecological Modulation Approach

“…Oral biofilm control is a key factor for maintaining oral health and preventing several oral diseases. Mechanical control of oral biofilms is first-line treatment, often supplemented with antiseptics or antibiotics (Cuenca et al 2021). Emerging problems with antimicrobials prompted the search for alternatives to control oral biofilms.…”

“…Controlling biofilms is challenging, especially when the biofilms are polymicrobial (as in oral biofilms). Cohabitating in a biofilm structure gives the bacterial cells increased protection against antimicrobials and host immune responses, partially due to the extracellular polysaccharide matrix (EPS) that embeds the cells (Vlad et al 2018;Cuenca et al 2021). This necessitates the use of mechanical and chemical interventions with broad-spectrum antimicrobials, as opposed to a species-specific antimicrobial agent (Zupančič et al 2018).…”

The Potential of 24-Propylcholestrol as Antibacterial Oral Bacteria of Enterococcus faecalis ATCC 29212 and Inhibitor Biofilms Formation: in vitro and in silico Study

“… 3 , 4 Currently, biofilms are considered to be the main mediators of dental infection and increase bacterial metabolism and virulence. 5 The formation of biofilms can cause poor conditions and increase resistance to antibacterial treatment 6 and the host’s immune system elements by preventing their penetration through the bacterial surfaces. 7 Nowadays, it is imperative to develop novel antibacterial agents active against both drug-sensitive and drug-resistant bacterial infections with favorable profiles as high efficacy, low toxicity, and short therapy duration.…”