, 2006). Moreover,

biofilms represent the overwhelming bacterial phenotype associated with chronic nonhealing wounds such as venous and diabetic ulcers, pressure sores, and burn wounds. These infections are often complex polymicrobial and polykingdom communities (Davis et al., 2006; Wolcott & Ehrlich, 2008). These chronic wound infections and foreign body infections associated with implantable medical devices and indwelling catheters (Ehrlich et al., 2004, 2005; Stoodley et al., 2005, 2008) are nearly impossible to eradicate without aggressive debridement and removal of the device, and have become the bane of many permanent and long-term interventional strategies, including artificial joints, central vascular lines, urinary catheterizations, Ridaforolimus order cardiac pace makers and defibrillators, ventricular-peritoneal shunts, and dialysis ports (reviewed in Ehrlich et al., 2004). These observations of bacterial phenotype are important because both transformation and mating have been demonstrated to be up to 104-fold higher in biofilms than in planktonic forms (Molin & Tolker-Nielsen, 2003; Sorenson et al., 2005). High transformation rates in biofilms likely result from the fact that one of the major constituents Nutlin-3a datasheet of the biofilm matrix is eDNA (Fig. 2), thus providing a ready source of genetic raw material. In the case of mating, the close spatial juxtaposition of bacterial cells in the biofilm and the physical stability conferred by the biofilm matrix likely

support pilus attachment and reduce the likelihood that the conjugal bridges through which the donor DNA is exported will be broken due to hydrodynamic shear stresses. The Bakaletz lab has further demonstrated that the biofilm matrix of H. influenzae, in addition to containing DNA, also contains very high Sulfite dehydrogenase concentrations

of type IV pili (Jurcisek & Bakaletz, 2007). Subsequently, Juhas et al. (2007a, b) demonstrated that some H. influenzae strains encode pilus genes that have been shown to support conjugal DNA transfer. The biofilm matrices of all bacterial species that have been characterized for molecular composition including P. aeruginosa, H. influenzae, S. pneumoniae, Streptococcus mutans, S. aureus, and Enterococcus faecalis contain large amounts of eDNA (Whitchurch et al., 2002; Jurcisek & Bakaletz, 2007; Hall-Stoodley et al., 2008; Mann et al., 2009; Perry et al., 2009; Thomas et al., 2009). Even more interestingly, the laboratories of Shi, Clavery, Havarstein, Cvitkovitch, and Hancock have convincingly demonstrated a temporal link between conspecific fratricide and the development of competence among the streptococci and the enterococci as a means to ensure a source of species-specific eDNA for those cells first becoming competent (able to take up foreign DNA). The streptococci, just before they become competent, produce and release bacteriocins that will kill their neighbors, thus ensuring a ready supply of DNA for transformation (Kreth et al.