The Effect of Biofilm Disruption on Growth and Metabolism of Pseudomonas aeruginosa PAO1

Abstract

Disruption of Pseudomonas aeruginosa PAO1 biofilms with alginate lyase has been shown to increase antibiotic susceptibility while physical disruption of the biofilm has not. The current study examined whether cell division and synthesis of RNA, DNA and protein differed between cells that were physically disrupted in the presence or absence of alginate lyase. Incorporation of radioactive uracil, thymine and glycine was used to assess RNA, DNA and protein synthesis, respectively, over a 4 hour time course. Plate counts were used to assess cell number at each time point. Cells treated with alginate lyase were found to increase specific incorporation of uracil, thymine and glycine until 2 hours, after which the levels decreased. This coincided with the time when treated cells began to divide. In contrast, the untreated cells were capable of synthesizing RNA, DNA and protein to high levels, but were unable to divide. The results indicate that, while macromolecule synthesis did not vary between alginate lyase treated and untreated cells, the ability of those cells to divide did. This may account for the differential antibiotic susceptibility of physically disrupted versus alginate lyase treated P. aeruginosa PAO1 cells.