A study on the long term effect of biofilm produced by biosurfactant producing microbe on medical implant

Area of Science:

• Biomaterials Science
• Microbiology
• Polymer Science

Background:

• Low density polyethylene (LDPE) is a common long-term medical implant material.
• Long-term studies on biofilm formation on medical implants are scarce.
• Pathogenic microorganisms can form biofilms on implanted polymers, potentially affecting device performance and patient health.

Purpose of the Study:

• To investigate the long-term (one year) biofilm formation of Bacillus subtilis and Pseudomonas aeruginosa on LDPE medical implants.
• To compare the biofilm properties, including exopolysaccharide (EPS) and biosurfactant production, between the two microorganisms.
• To assess the impact of biofilm formation on the material properties of LDPE.

Main Methods:

• Culturing B. subtilis and P. aeruginosa on LDPE samples over a one-year period.
• Quantifying microbial colony counts and measuring EPS and biosurfactant concentrations.
• Analyzing biofilm composition using mass spectrometry to identify specific biosurfactants (surfactins and rhamnolipids).
• Evaluating LDPE degradation using thermogravimetric analysis (TGA).
• Detecting enzymatic activity (laccase, manganese peroxidase) within the biofilms.

Main Results:

• B. subtilis exhibited significantly higher colony counts than P. aeruginosa, increasing over time.
• EPS and biosurfactant production by B. subtilis surpassed that of P. aeruginosa throughout the study.
• LDPE showed increased weight loss after incubation with both microorganisms, particularly after one year.
• Proteins involved in community control and sporulation were found in B. subtilis biofilms, while P. aeruginosa biofilms contained housekeeping proteins.
• Biosurfactants altered surface hydrophobicity, promoting microbial attachment and proliferation.

Conclusions:

• B. subtilis demonstrates a greater propensity for biofilm formation on LDPE medical implants compared to P. aeruginosa over extended periods.
• The differing biofilm compositions and increased EPS/biosurfactant production by B. subtilis suggest distinct interactions with the LDPE surface.
• The observed material degradation and presence of enzymes indicate that biofilms can compromise the integrity of LDPE implants.
• Understanding these microbial interactions is crucial for developing strategies to prevent biofilm-related complications in medical implants.