Identification of biofilm proteins in non-typeable Haemophilus Influenzae

265 proteins were identified in the extracellular matrix sample. The identified proteins were analyzed for COG grouping and predicted cellular location via the TMHMM and SignalP predictive algorithms. The most over-represented COG groups identified compared to their frequency in the Haemophilus influenzae genome were cell motility and secretion (group N) followed by ribosomal proteins of group J. A number of hypothetical or un-characterized proteins were observed, as well as proteins previously implicated in biofilm function.This study represents an initial approach to identifying and cataloguing numerous proteins associated with biofilm structure. The approach can be applied to biofilms of other bacteria to look for commonalities of expression and obtained information on biofilm protein expression can be used in multidisciplinary approaches to further understand biofilm structure and function.Bacteria exist in both planktonic and biofilm states [1,2]. Recent findings indicate chronic infections are associated with the formation of in vivo biofilm which renders the bacteria resistant to antibiotic treatment [3]. This resistance has been believed to be due to the structural properties of the biofilm which have been described as "matrix encased microbrial communities" [4]. More recently, studies of Pseudomonas aeruginosa biofilm indicated that simple lack of anti-biotic penetration is not the cause of resistance [5] and "anoxic regions where bacteria are poorly killed due to very low metabolic rates" in has been hypothesized [6]. Formation of biofilm includes adherence events wherein the bacteria become sessile and secrete extracellular matrix. The end result is a highly structured multicellular complex with cavities and channels [2]. Historically, molecular and biochemical studies of bacteria have examined the planktonic state rather than biofilm state. Understanding the molecular nature of the biofilm structure is of interest in developing strategies to combat chron