Bacteriophages and Biofilms

TLDR

Biofilms are a common bacterial adaptation that shields bacteria from antibiotics and biocides through an extracellular matrix and persister cells, rendering these chemicals largely ineffective against them. Bacteriophages exploit the dense bacterial population in biofilms to rapidly infect and amplify, while enzymes they produce degrade the extracellular matrix and their ability to infect persister cells allows them to target dormant bacteria. Bacteriophages demonstrate a greater ability to target and replicate within biofilms compared to planktonic bacteria, with cultured biofilms supporting higher phage replication.

Abstract

Biofilms are an extremely common adaptation, allowing bacteria to colonize hostile environments. They present unique problems for antibiotics and biocides, both due to the nature of the extracellular matrix and to the presence within the biofilm of metabolically inactive persister cells. Such chemicals can be highly effective against planktonic bacterial cells, while being essentially ineffective against biofilms. By contrast, bacteriophages seem to have a greater ability to target this common form of bacterial growth. The high numbers of bacteria present within biofilms actually facilitate the action of bacteriophages by allowing rapid and efficient infection of the host and consequent amplification of the bacteriophage. Bacteriophages also have a number of properties that make biofilms susceptible to their action. They are known to produce (or to be able to induce) enzymes that degrade the extracellular matrix. They are also able to infect persister cells, remaining dormant within them, but re-activating when they become metabolically active. Some cultured biofilms also seem better able to support the replication of bacteriophages than comparable planktonic systems. It is perhaps unsurprising that bacteriophages, as the natural predators of bacteria, have the ability to target this common form of bacterial life.