Role of autolysin-mediated DNA release in biofilm formation of Staphylococcus epidermidis

Abstract

Staphylococcus epidermidis has become a serious nosocomial pathogen frequently causing infections associated with implanted foreign materials. Biofilm formation is considered a major factor determining S. epidermidis pathogenicity in such device-associated infections. Here, evidence is presented that extracellular DNA is important for the initial phase of biofilm development by S. epidermidis on polystyrene or glass surfaces under static or hydrodynamic conditions. Comparative PCR amplification from S. epidermidis chromosomal and extracellular DNA indicated that the extracellular DNA is similar to chromosomal DNA. Experiments involving the S. epidermidis wild-type and an isogenic atlE mutant indicated that most of the extracellular DNA in S. epidermidis cultures and biofilms is generated through activity of the autolysin AtlE. The presented results suggest that extracellular DNA is generated in S. epidermidis populations through AtlE-mediated lysis of a subpopulation of the bacteria, and that the extracellular DNA promotes biofilm formation of the remaining population.

Phage-induced lysis enhances biofilm formation in Shewanella oneidensis MR-1

“…In contrast, the significance of eDNA for cellular attachment and structural integrity has more recently been recognized for an increasing number of Gram-negative and Grampositive species (Whitchurch et al, 2002;Steinberger and Holden, 2005;Allesen-Holm et al, 2006;Moscoso et al, 2006;Jurcisek and Bakaletz, 2007;Qin et al, 2007;Izano et al, 2008;Thomas et al, 2008;Heijstra et al, 2009;Vilain et al, 2009;Harmsen et al, 2010;Lappann et al, 2010). Release of DNA in bacterial biofilms has mainly been attributed to the lysis of a cellular subpopulation, mediated by the activity of autolysis systems (Allesen-Holm et al, 2006;Rice et al, 2007;Thomas et al, 2008Thomas et al, , 2009Mann et al, 2009).…”

“…Other factors implicated in cell lysis are toxin/antitoxin system that have been characterized, for example, in Enterococcus faecalis (Thomas et al, 2008) and Staphylococcus sp. (Qin et al, 2007;Rice et al, 2007;Mann et al, 2009). However, a role for toxin/antitoxin systems in biofilm formation is not necessarily directly linked to cell lysis, as has been demonstrated for E. coli (Kim et al, , 2010.…”

Sticky Situations: Key Components That Control Bacterial Surface Attachment

“…Whitchurch et al (166) first demonstrated that P. aeruginosa PAO1 biofilm formation was significantly reduced under flowing conditions in the presence of DNase. eDNA has been subsequently shown to contribute to biofilm formation by clinical P. aeruginosa isolates as well as by a variety of bacterial species, including Staphylococcus epidermidis, through analyses of biofilm formation by lysis-defective mutants and of DNA removal from the biofilm matrix (67,117,133,146,150). The contribution of eDNA to attachment and biofilm formation, however, appears to be temporal: experiments utilizing DNase I have suggested that cells in young PAO1 biofilms are held together by eDNA, whereas the cells in more-mature PAO1 biofilms are held together primarily by components other than eDNA (98,166).…”

Anti-virulence Strategies to Target Bacterial Infections

“…To target biofilm formation to inhibit persistence and recurrent infection, substances are being investigated that can inhibit secretion of biofilm components, biofilm matrix formation or destroy or resolve existing biofilm matrices. Furthermore, DNase I can degrade the extracellular DNA present in the biofilm matrix (Okshevsky et al 2015;Qin et al 2007), interfering with its formation and stability as shown for Bordetella pertussis (Conover et al 2011), Listeria monocytogenes (Harmsen et al, 2010), and Campylobacter jejuni (Brown et al 2015). A bacterial glycoside hydrolase, named Dispersin B, has been isolated from Actinobacillus actinomycetemcomitans, which was shown to disrupt mature Actinobacillus biofilms (Rasko et al 2008;Stephenson et al 2000;Wilke et al 2015;Worthington et al 2013).…”