Antibiotic-Induced Biofilm Formations in Pseudomonas aeruginosa Strains KPW.1-S1 and HRW.1-S3 are Associated with Increased Production of eDNA and Exoproteins, Increased ROS Generation, and Increased Cell Surface Hydrophobicity

Area of Science:

• Microbiology
• Infectious Diseases
• Biomedical Engineering

Background:

• * Pseudomonas aeruginosa is an opportunistic pathogen known for forming biofilms, a key survival mechanism.
• * Biofilm formation on medical implants poses significant clinical challenges.
• * Sub-minimum inhibitory concentration (sub-MIC) levels of antibiotics may paradoxically promote biofilm formation.

Purpose of the Study:

• * To investigate the effect of the aminoglycoside antibiotic gentamicin on the biofilm dynamics of Pseudomonas aeruginosa.
• * To analyze how gentamicin influences biofilm components and bacterial cell characteristics.

Main Methods:

• * Two strains of Pseudomonas aeruginosa (KPW.1-S1 and HRW.1-S3) were treated with varying concentrations of gentamicin.
• * Biofilm formation was quantified.
• * Confocal and scanning electron microscopy were employed.
• * Biochemical tests assessed exopolymeric substances (exoproteins, eDNA, exolipids), reactive oxygen species (ROS), and cell surface hydrophobicity.

Main Results:

• * Gentamicin exposure led to increased biofilm formation in both Pseudomonas aeruginosa strains.
• * Elevated concentrations of gentamicin correlated with greater biofilm production.
• * Gentamicin treatment increased exopolymeric substances, ROS generation, and cell surface hydrophobicity.
• * Enhanced cell adherence was observed under gentamicin stress.

Conclusions:

• * Sub-inhibitory concentrations of gentamicin promote Pseudomonas aeruginosa biofilm formation.
• * Increased biofilm components and cell surface hydrophobicity contribute to enhanced biofilm production under antibiotic stress.
• * Findings highlight potential risks of using sub-lethal antibiotic doses in treating Pseudomonas aeruginosa infections.