How Do Phages Disrupt the Structure of Enterococcus faecalis Biofilm?

Abstract

Biofilms are composed of multicellular communities of microbial cells and their self-secreted extracellular polymeric substances (EPS). The viruses named bacteriophages can infect and lyze bacterial cells, leading to efficient biofilm eradication. The aim of this study was to analyze how bacteriophages disrupt the biofilm structure by killing bacterial cells and/or by damaging extracellular polysaccharides, proteins, and DNA. The use of colorimetric and spectrofluorimetric methods and confocal laser scanning microscopy (CLSM) enabled a comprehensive assessment of phage activity against E. faecalis biofilms. The impact of the phages vB_Efa29212_2e and vB_Efa29212_3e was investigated. They were applied separately or in combination on 1-day and 7-day-old biofilms. Phages 2e effectively inhibited the growth of planktonic cells with a limited effect on the biofilm. They did not notably affect extracellular polysaccharides and proteins; however, they increased DNA levels. Phages 3e demonstrated a potent and dispersing impact on E. faecalis biofilms, despite being slightly less effective than bacteriophages 2e against planktonic cells. Phages 3e reduced the amount of extracellular polysaccharides and increased eDNA levels in both 1-day-old and 7-day-old biofilm cultures. Phage cocktails had a strong antimicrobial effect on both planktonic and biofilm-associated bacteria. A significant reduction in the levels of polysaccharides, proteins, and eDNA in 1-day-old biofilm samples was noted, which confirms that phages interfere with the structure of E. faecalis biofilm by killing bacterial cells and affecting extracellular polymer levels.

Strategies and mechanisms targeting Enterococcus faecalis biofilms associated with endodontic infections: a comprehensive review

“…Additionally, phage-produced depolymerases degrade the EPS matrix in biofilms, destabilizing the biofilm and allowing for deeper penetration and more effective eradication ( Figure 3 ). 4) Phages disrupt bacterial communication systems, such as QS, thereby interfering with the regulatory processes critical for biofilm maintenance and stability ( Khalifa et al., 2016 ; Moryl et al., 2023 ) ( Figure 4 ). These combined mechanisms highlight the potential of phage therapy in effectively targeting and eradicating biofilms.…”

The Antibacterial Activity of Novel Bacteriophages and the Emergence of Bacterial Resistance to Phage Infections: An In Vitro Study

“…In the food industry, biofilms on stainless steel surfaces have been reported and are considered a risk to consumer food safety [12]. In this context, phages with the capacity to infect P. aeruginosa, E. coli, E. faecalis and S. aureus have already been reported [13][14][15] and are relevant for directing further studies on strategies to combat bacterial contamination and/or infections in several areas, such as human health, water treatment [1], agriculture [2], the food industry [3] and animal husbandry [4].…”