Figure 2.

Schematic diagram of targeted delivery of extracellular glycoside hydrolase by engineered bacteria to destroy Pseudomonas aeruginosa biofilm. The biofilm formation and virulence-related genes pelA-B, pelF, and T3SS of P. aeruginosa were knocked out as parental strains, and exogenous recombinant vectors were introduced to overexpress the exopolysaccharide hydrolases PelA and PslG. PelA and PslG accumulated in cells and were then released into the extracellular matrix through cell lysis. There are two ways in which hydrolases are released into the extracellular matrix. The first is through regulating the prtN gene to activate the expression of cell lysis protein genes, thereby releasing PelA and PslG. The second is by deleting the Pf4 filamentous prophage-encoding gene cluster to sensitize it to the Pf4 phage in biofilms, thereby initiating the passive lysis mechanism of its own cells to release PelA and PslG. The PelA and PslG are released to the extracellular matrix to destroy the biofilm skeleton components Pel and Psl through enzymatic hydrolysis, thereby destroying the P. aeruginosa biofilm.