Biofilm formation by Pseudomonas aeruginosa and disinfectant susceptibility of planktonic and biofilm cells

Abstract

Epifluorescence microscopy (EFM) was used to study the biofilm formation of Pseudomonas aeruginosa after 6, 24, 30, 48, 54, 72, 78, and 96 h growth in a chamber slide system. For this purpose, the biofilm was stained with the Live/Dead BacLight, wherein live and dead cells were visualised based on the cell membrane integrity. With the use of EFM we described 8- of 9-stage biofilm characteristics after 78 h of growth, since the majority of microscopic fields were fully covered with attached cells. However, the 96-h growth resulted in the cell detachment and revealed 30% of dead cells of all those cells that remained on the surface. The susceptibility testing of planktonic and biofilm cells to two disinfectants, chlorine-based and quaternary ammonium compound-based, revealed that biofilm cells were more tolerant to a chlorine-based sanitiser than planktonic counterparts. P. aeruginosa was inhibited by lower concentrations of the quaternary ammonium compound-based sanitiser than the chlorine-based sanitiser, which on the other hand was more effective in cell inactivation, as both the MIC/MBC (inhibitory/bactericidal) measurement and the CFDA/PI (carboxyfluorescein diacetate/propidium iodide) staining indicated.

Genomic Variability Correlates with Biofilm Phenotypes in Multidrug Resistant Clinical Isolates of Pseudomonas aeruginosa

“…As bio lm formation is dependent on various genetic and environmental factors, there is no consistent approach for the control of bio lms and control strategies against bio lms formed by pathogenic bacteria should be directed on a case-by-case basis [14,15]. Genomic and phenotypic variability among bio lm producing strains make anti-bio lm therapy more complicated.…”