title: A study on the long term effect of biofilm produced by biosurfactant producing microbe on medical implant.
abstract: Low density polyethylene (LDPE) is used as a long term medical implant. Biofilm forming ability of two pathogenic microorganisms, namely, Bacillus subtilis (B. subtilis) and Pseudomonas aeruginosa (P. aeruginosa) on this polymer and the differences in the properties of these matrices are studied for a year. There are very few long term studies on biofilms formed on medical implants. After three months, colonies of B. subtilis were two times higher when compared to those of P. aeruginosa. And at the end of one year, they were two orders of magnitude higher than the later. The exopolysaccharide (EPS) and biosurfactant recovered from the polymer surface after three months were 21 and 10.4 μg/cm(2) for B. subtilis and 13 and 8.6 μg/cm(2) for P. aeruginosa. After one year, these were higher in B. subtilis (50 and 37.1 μg/cm(2), respectively) than in P. aeruginosa (34.1 and 31.8 μg/cm(2), respectively). B. subtilis consisted of protein controlling the community and sporulation development, while P. aeruginosa had either housekeeping or metabolic proteins. The EPS in the respective biofilm consisted of biosurfactants produced by B. subtilis (surfactins, m/z=1029 to 1134) and P. aeruginosa (rhamnolipids, m/z=568 to 705). Thermogravimetric analysis indicated that LDPE incubated with these organisms underwent a weight loss of 4 and 3% after three months and 11.1 and 9.2% after one year, respectively at 435 °C. Laccase and manganese peroxidase were detected in the biofilm which could be involved in the degradation. The biosurfactant of these microorganisms altered the hydrophobicity of the surface, favoring their attachment and proliferation.
authors.affiliation: Department of Biotechnology, Bhupat & Jyoti Mehta School of BioSciences Building, IIT Madras, Chennai 600036, India.
authors.forename: Veluchamy
authors.initials: V
authors.lastname: Prabhawathi
authors.affiliation: Department of Biotechnology, Bhupat & Jyoti Mehta School of BioSciences Building, IIT Madras, Chennai 600036, India.
authors.forename: Kathirvel
authors.initials: K
authors.lastname: Thirunavukarasu
authors.affiliation: Department of Biotechnology, Bhupat & Jyoti Mehta School of BioSciences Building, IIT Madras, Chennai 600036, India. Electronic address: mukeshd@iitm.ac.in.
authors.forename: Mukesh
authors.initials: M
authors.lastname: Doble
mesh_terms: D001412:Bacillus subtilis / Q000502:physiology*; D018441:Biofilms / Q000187:drug effects / Q000254:growth & development*; D042845:Laccase / Q000378:metabolism; D010544:Peroxidases / Q000378:metabolism; D020959:Polyethylene / Q000737:chemistry / Q000494:pharmacology; D011135:Polysaccharides, Bacterial / Q000737:chemistry / Q000378:metabolism; D019736:Prostheses and Implants / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000502:physiology*
chemical_list: D011135:Polysaccharides, Bacterial; C085953:exopolysaccharide, Bacillus; C064841:exopolysaccharide, Pseudomonas; D020959:Polyethylene; D042845:Laccase; D010544:Peroxidases; C051129:manganese peroxidase
keywords: Bacillus subtilis; Biofilm; Biosurfactants; Low-density polyethylene; MALDI-TOF; Pseudomonas aeruginosa