For this reason, methods for continued monitoring of biofilm growth where the biofilm does not need to be labelled or manipulated have been proposed as a powerful alternative to traditional staining procedures. In addition, classical biofilm mass quantification usually provides high standard deviations, and can result in lack of reproducibility due to manipulation steps. Although bacterial biofilms have been deeply investigated during the past decades, a major limitation is that most existing methods for biofilm research provide information at a single endpoint, therefore missing relevant features about the growth and persistence dynamics. Thus, biofilms have already been described to be up to 1000 times more resistant to antibiotics compared to their planktonic forms and exhibit a large threat to human health. This matrix is mainly composed of macromolecules including DNA, proteins and polysaccharides and has a very selective permeability to nutrients and antimicrobial compounds. As the tested ciprofloxacin-mannitol combination appeared to fully eradicate mature biofilms, we conclude that impedance-based biofilm diagnostics, which permits antibiotic susceptibility testing and the identification of persister cells, is of great potential for the clinical practice and could aid in establishing treatment breakpoints for emerging biofilm-related infections.īiofilms can be described as bacterial communities immobilized in a self-secreted biopolymeric matrix. These results were confirmed using viable colony counting. When administered at doses ≥320 mg/L, mannitol was capable of preventing persister cell formation by efficiently activating dormant bacteria and making them susceptible to the antibiotic. Given that mannitol has been proposed to activate bacterial metabolism, the synergistic combination of mannitol and ciprofloxacin was evaluated on clinical 48 h P. However, these mutations were not uniquely associated with persisters, suggesting that the persistent phenotype may be related to metabolic and transcriptional changes. Whole-genome sequencing of wildtype and persister cells identified several SNPs, a genomic inversion and a genomic duplication in one of the strains. aeruginosa biofilms to certain concentrations of ciprofloxacin, ceftazidime and tobramycin induced the emergence of persister cells, that showed different morphology and pigmentation, as well increased antibiotic resistance. Real-time growth quantifications revealed that the exposure of established P. Using impedance-based measurements, crystal violet staining and traditional culture we have studied the biofilm growth dynamics of 13 Pseudomonas aeruginosa strains under the effect of seven conventional antibiotics. Biofilm formation and the appearance of persister cells with low metabolic rates are key factors affecting conventional treatment failure and antibiotic resistance.
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