DESIGN: Here, we have investigated these individual plant extracts and its synergistic mixture (PEM) for its anti-cariogenic effect to reduce populations of single and mixed-species of Streptococcus sanguinis and Streptococcus mutans in a planktonic or/and biofilm and their others reduced virulence. Bacterial populations in the biofilm after 24 h, hydrophobic cell surface activity to n-hexadecane and pH changes at 5 min' intervals until 90 min of incubation were recorded. Total phenolic content and bioactive compounds in the crude aqueous plant extracts were analysed. Regulatory gene expressions of S. mutans adhesins genes (gtfB, gtfC, gbpB and spaP) upon treatment with PEM were investigated in planktonic and biofilm conditions.
RESULTS: All plant extracts strongly reduced S. mutans in the biofilm compared to S. sanguinis in single and mixed-species. PEM reduced S. mutans by 84% with S. sanguinis 87% in the mixed population. Psidium sp. and PEM highly reduced cell-surface hydrophobicity of the two bacteria thus reducing adherence and biofilm formation. PEM and Mangifera sp. lowered initial pH change in the mixed populations of S. sanguinis and S. mutans. PEM downregulated the S. mutans gtfB gene expression in the single species planktonic and mixed-species biofilms.
CONCLUSIONS: The effectiveness of PEM in reducing S. mutans within the biofilm, cell-surface hydrophobicity, acid production and adhesin gene (gtfB) expression in mixed-species with S. sanguinis indicates its potential as an antibacterial agent against dental caries. This is attributed to the phenolic content in the PEM.
METHODS: The study was carried out from September 2017 to February 2019. Four archive isolates forming strong and intermediate biofilm and non-biofilms producer were subcultured from archive isolates. ATCC 27853 P. aeruginosa was used as a negative control or non-biofilm producing microorganism. Biofilm formation was confirmed by Crystal Violet Assay (CVA) and Congo Red Agar (CRA). Metabolic profiles of the biofilm and non-biofilms isolates were determined by phenotype microarrays (Biolog Omnilog).
RESULTS AND DISCUSSION: In this study, Pseudomonas aeruginosa biofilm isolates utilized uridine, L-threonine and L-serine while non-biofilm utilized adenosine, inosine, monomethyl, sorbic acid and succinamic acid.
CONCLUSION: The outcome of this result will be used for future studies to improve detection or inhibit the growth of P. aeruginosa biofilm and non-biofilm respectively.
OBJECTIVES: Biofilms, which are made mostly of the matrix can be thought of as communities of microbes that are more virulent and more difficult to eradicate as compared to their planktonic counterparts. Currently, several formulations are available in the market which have the potential to treat biofilm-assisted skin disorders. However, the existing pharmacotherapies are not competent enough to cure them effectively and entirely, in several cases.
KEY FINDINGS: Especially with the rising resistance towards antibiotics, it has become particularly challenging to ameliorate these disorders completely. The new approaches are being used to combat biofilm-associated skin disorders, some of them being photodynamic therapy, nanotherapies, and the use of novel drug delivery systems. The focus of attention, however, is nanotherapy. Micelles, solid lipid nanoparticles, quatsomes, and many others are being considered to find a better solution for the biofilm-associated skin disorders.
SIGNIFICANCE: This review is an attempt to give a perspective on these new approaches for treating bacterial biofilms associated with skin disorders.
OBJECTIVE: The mechanisms of bacterial resistance are described in this review and this is followed by an outline of the features and uses of metallic NPs as antibiotic agents to address bacteria that are antibiotic- sensitive and resistant. Additionally, a general impression of metallic NPs as antibiofilm bactericidal agents is presented.
CONCLUSION: Biofilms and bacterial strains that are resistant to antibiotics present a grave public health challenge and this has enhanced the need to develop new bactericidal agents. Therefore, nanomaterials are considered as a potential platform for managing bacterial infections.