Uncovering the phenotypic and transcriptional characteristics of biofilm-released cells in Pseudomonas aeruginosa

Abstract

Pseudomonas aeruginosa is a prominent biofilm-forming pathogen associated with chronic infections that are difficult to eradicate due to the protective biofilm matrix. Inducing biofilm dispersion has emerged as a potential therapeutic strategy. Although researchers have compared selected biofilm dispersion mechanisms, the characteristics of cells generated by mechanistically distinct release strategies, particularly enzymatic matrix degradation, remain uncharacterized. In this study, we compared P. aeruginosa cells released from biofilms using four distinct dispersion mechanisms: An external signaling molecule (cis-2-decenoic acid; cis-DA), a nutrient cue (glutamate), an environmental toxin (sodium nitroprusside; SNP), and a matrix-degrading enzyme (amylase). Released cells exhibited distinct antibiotic susceptibility, attachment, and gene expression depending on the release mechanism. Glutamate-released cells exhibited greater tobramycin tolerance and attachment, whereas glutamate and amylase-released populations exhibited differences in the expression of selected genes. Additionally, the release mechanism influenced subsequent biofilm recovery and reformation, and cis-DA significantly enhanced tobramycin-mediated killing of mature biofilms. Collectively, these findings demonstrate that the mechanism used to induce release may influence subsequent bacterial behavior and antibiotic susceptibility. These findings highlight the importance of considering release mechanism when developing dispersion-based strategies for treating biofilm-associated infections.