Topic
Biofilm matrix
About: Biofilm matrix is a research topic. Over the lifetime, 1589 publications have been published within this topic receiving 110140 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: It is found that the extracellular matrix produced by Pseudomonas aeruginosa self-assembles into a liquid crystal through entropic interactions between polymers and filamentous Pf bacteriophages, which are long, negatively charged filaments, which enhance biofilm function by increasing adhesion and tolerance to desiccation and antibiotics.
189 citations
TL;DR: F fungus provides the bacterium with enhanced tolerance to antimicrobial drugs when grown together, and a specific antifungal agent indirectly sensitized the bacteria to antimicrobials by inhibiting the production of the fungal polysaccharides.
Abstract: Biofilm-associated polymicrobial infections, particularly those involving fungi and bacteria, are responsible for significant morbidity and mortality and tend to be challenging to treat. Candida albicans and Staphylococcus aureus specifically are considered leading opportunistic fungal and bacterial pathogens, respectively, mainly due to their ability to form biofilms on catheters and indwelling medical devices. However, the impact of mixed-species biofilm growth on therapy remains largely understudied. In this study, we investigated the influence of C. albicans secreted cell wall polysaccharides on the response of S. aureus to antibacterial agents in biofilm. Results demonstrated significantly enhanced tolerance for S. aureus to drugs in the presence of C. albicans or its secreted cell wall polysaccharide material. Fluorescence confocal time-lapse microscopy revealed impairment of drug diffusion through the mixed biofilm matrix. Using C. albicans mutant strains with modulated cell wall polysaccharide expression, exogenous supplementation, and enzymatic degradation, the C. albicans-secreted β-1,3-glucan cell wall component was identified as the key matrix constituent providing the bacteria with enhanced drug tolerance. Further, antibody labeling demonstrated rapid coating of the bacteria by the C. albicans matrix material. Importantly, via its effect on the fungal biofilm matrix, the antifungal caspofungin sensitized the bacteria to the drugs. Understanding such symbiotic interactions with clinical relevance between microbial species in biofilms will greatly aid in overcoming the limitations of current therapies and in defining potential new targets for treating polymicrobial infections. IMPORTANCE The fungus Candida albicans and the bacterium Staphylococcus aureus are important microbial pathogens responsible for the majority of infections in hospitalized patients and are often coisolated from a host. In this study, we demonstrated that when grown together, the fungus provides the bacterium with enhanced tolerance to antimicrobial drugs. This process was mediated by polysaccharides secreted by the fungal cell into the environment. The biofilm matrix formed by these polysaccharides prevented penetration by the drugs and provided the bacteria with protection. Importantly, we show that by inhibiting the production of the fungal polysaccharides, a specific antifungal agent indirectly sensitized the bacteria to antimicrobials. Understanding the therapeutic implications of the interactions between these two diverse microbial species will aid in overcoming the limitations of current therapies and in defining new targets for treating complex polymicrobial infections.
188 citations
TL;DR: It is shown that both phenotypic and genetic strategies for a division of labor can promote collective biofilm formation in the soil bacterium Bacillus subtilis and that asymmetries in strain ratio can arise due to differences in the relative benefits that matrix compounds generate for the collective.
186 citations
TL;DR: The results suggest that Esp inhibits S. aureus colonization and biofilm formation by degrading specific proteins that are crucial for biofilm construction and host-pathogen interaction.
Abstract: Staphylococcus aureus exhibits a strong capacity to attach to abiotic or biotic surfaces and form biofilms, which lead to chronic infections. We have recently shown that Esp, a serine protease secreted by commensal Staphylococcus epidermidis, disassembles preformed biofilms of S. aureus and inhibits its colonization. Esp was expected to degrade protein determinants of the adhesive and cohesive strength of S. aureus biofilms. The aim of this study was to elucidate the substrate specificity and target proteins of Esp and thereby determine the mechanism by which Esp disassembles S. aureus biofilms. We used a mutant Esp protein (Esp(S235A)) with defective proteolytic activity; this protein did not disassemble the biofilm formed by a clinically isolated methicillin-resistant S. aureus (MRSA) strain, thereby indicating that the proteolytic activity of Esp is essential for biofilm disassembly. Esp degraded specific proteins in the biofilm matrix and cell wall fractions, in contrast to proteinase K, which is frequently used for testing biofilm robustness and showed no preference for proteolysis. Proteomic and immunological analyses showed that Esp degrades at least 75 proteins, including 11 biofilm formation- and colonization-associated proteins, such as the extracellular adherence protein, the extracellular matrix protein-binding protein, fibronectin-binding protein A, and protein A. In addition, Esp selectively degraded several human receptor proteins of S. aureus (e.g., fibronectin, fibrinogen, and vitronectin) that are involved in its colonization or infection. These results suggest that Esp inhibits S. aureus colonization and biofilm formation by degrading specific proteins that are crucial for biofilm construction and host-pathogen interaction.
184 citations
TL;DR: Investigation of Pseudomonas putida in a biofilter for waste gas treatment revealed a very heterogeneous structure of the fully hydrated biofilm, which indicated that toluene may penetrate to deeper layers of theBiofilm, and consequently P. putida may be actively degrading toLUene in all regions of the biofilm.
Abstract: As a representative member of the toluene-degrading population in a biofilter for waste gas treatment, Pseudomonas putida was investigated with a 16S rRNA targeting probe. The three-dimensional distribution of P. putida was visualized in the biofilm matrix by scanning confocal laser microscopy, demonstrating that P. putida was present throughout the biofilm. Acridine orange staining revealed a very heterogeneous structure of the fully hydrated biofilm, with cell-free channels extending from the surface into the biofilm. This indicated that toluene may penetrate to deeper layers of the biofilm, and consequently P. putida may be actively degrading toluene in all regions of the biofilm. Furthermore, measurements of growth rate-related parameters for P. putida showed reduced rRNA content and cell size (relative to that in a batch culture), indicating that the P. putida population was not degrading toluene at a maximal rate in the biofilm environment. Assuming that the rRNA content reflected the cellular activity, a lower toluene degradation rate for P. putida present in the biofilm could be estimated. This calculation indicated that P. putida was responsible for a significant part (65%) of the toluene degraded by the entire community.
184 citations