Bacteriophage and associated polysaccharide depolymerases – novel tools for study of bacterial biofilms

Abstract

Bacteriophage for three representative strains of Gram‐negative biofilm bacteria have proved to be of widespread occurrence. Lytic bacteriophage have been isolated from local sewage for the bacterium 1·15, an exopolysaccharide (EPS)‐producing pseudomonad found originally as a component of biofilms in a local river, and for two Enterobacter agglomerans strains from industrial biofilms. Representative examples of all three bacteriophage possess a relatively low burst size and on solid media, exhibit very large plaques surrounded by a wide halo (5–20 mm) indicative of polysaccharide depolymerase action. The bacteriophage are thus similar to other viruses for EPS‐producing bacteria in inducing the synthesis of enzymes degrading the polymers which occlude the bacterial cell surface. In each preparation, the polysaccharase activity was associated both with sedimented phage particles and with the supernate of bacterial lysates. The enzymes have been partially purified and used to prepare polysaccharide digests in which the major products from each polysaccharide are the presumed repeat units of the polymers or oligomers of these. The soluble phage enzymes each degrade their substrate by acting as endo‐glycanohydrolases. The phage and their associated enzymes thus provide very useful highly specific tools for studies of biofilms incorporating the bacterial host strains. Their potential applications in studies on bacterial biofilms are discussed.

Fluorescence Correlation Spectroscopy To Study Diffusion and Reaction of Bacteriophages inside Biofilms

“…(10,12,13,15,49). They also suggested that the location and arrangement of the biofilm substratum cell matrix could partially mask phage receptor sites (18,27,28). Fluorescent labeling of c2 bacteriophage.…”

“…Novel "synthetic" biology technologies should enable the engineering of libraries of phages with biofilm-degrading enzymes mimicking natural polysaccharases or polysaccharide lyases (27,28,52). The resistance of L. lactis IL-1403 bacteria to c2 phage infection was confirmed by the lack of lytic activity of the phage with both free cells and biofilms.…”

“…However, the reaction of biofilms to ubiquitous viral particles in the environment is poorly documented (52). It is clearly essential to determine whether a bacteriophage can directly penetrate the glycocalix matrix, infect the bacteria, and ultimately degrade biofilms (27,28), as these fundamental ecological questions must be answered if we are to improve phage control.…”

Cholate-Stimulated Biofilm Formation by Lactococcus lactis Cells

“…The lactococcal cell wall consists of a thick peptidoglycan layer with interspersed teichoic and lipoteichoic acids, surface-exposed proteins, and polysaccharides (10). We focused on EPS in the biofilms because of their role in maintaining biofilm integrity (22) and promoting cell adhesion (8). Even in the absence of cholate, biofilms of the ⌬lmrCD r strain produced greater amounts of EPS than wild-type and ⌬lmrCD biofilms.…”

Complete Genome Sequence of the Novel Escherichia coli Phage phAPEC8

“…It was already suggested that the sialidase activity of K1-dependent phages provides an increased fitness on capsule-bearing E. coli cells in serum and thus these phages might be more efficient in phage therapy (5). The polysaccharase activity of a predicted protein similar to the colanic acid-degrading protein of phage NST1 (accession number HM214492.1) could allow the phage to penetrate into biofilms (8). Bacterial capsular polysaccharides and colanic acid are both considered virulence factors of APEC (6,12).…”