title: Host Responses to Biofilm.
abstract: From birth to death the human host immune system interacts with bacterial cells. Biofilms are communities of microbes embedded in matrices composed of extracellular polymeric substance (EPS), and have been implicated in both the healthy microbiome and disease states. The immune system recognizes many different bacterial patterns, molecules, and antigens, but these components can be camouflaged in the biofilm mode of growth. Instead, immune cells come into contact with components of the EPS matrix, a diverse, hydrated mixture of extracellular DNA (bacterial and host), proteins, polysaccharides, and lipids. As bacterial cells transition from planktonic to biofilm-associated they produce small molecules, which can increase inflammation, induce cell death, and even cause necrosis. To survive, invading bacteria must overcome the epithelial barrier, host microbiome, complement, and a variety of leukocytes. If bacteria can evade these initial cell populations they have an increased chance at surviving and causing ongoing disease in the host. Planktonic cells are readily cleared, but biofilms reduce the effectiveness of both polymorphonuclear neutrophils and macrophages. In addition, in the presence of these cells, biofilm formation is actively enhanced, and components of host immune cells are assimilated into the EPS matrix. While pathogenic biofilms contribute to states of chronic inflammation, probiotic Lactobacillus biofilms cause a negligible immune response and, in states of inflammation, exhibit robust antiinflammatory properties. These probiotic biofilms colonize and protect the gut and vagina, and have been implicated in improved healing of damaged skin. Overall, biofilms stimulate a unique immune response that we are only beginning to understand.
authors: Wound Infections Department, Naval Medical Research Center, Silver Spring, MD, United States.
authors: C
authors: C
authors: Watters
authors: Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, United States; Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States.
authors: D
authors: D
authors: Fleming
authors: Wound Infections Department, Naval Medical Research Center, Silver Spring, MD, United States.
authors: D
authors: D
authors: Bishop
authors: Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, United States; Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States. Electronic address: kendra.rumbaugh@ttuhsc.edu.
authors: K P
authors: KP
authors: Rumbaugh
mesh_terms: D000818:Animals; D018441:Biofilms / Q000187:drug effects; D054884:Host-Pathogen Interactions / Q000187:drug effects; D006801:Humans; D007107:Immune System / Q000187:drug effects / Q000382:microbiology; D008954:Models, Biological; D019936:Probiotics / Q000494:pharmacology; D012867:Skin / Q000187:drug effects / Q000276:immunology
keywords: EPS matrix; Lactobacillus biofilms; M2 macrophages; Pseudomonas aeruginosa; Staphylococcus aureus; bacterial immune response; biofilms; extracellular DNA; neutrophil lysis; probiotics