XXI ALAM
Resumo:247-1


Prêmio
247-1Plasma surface modification of polystyrene inhibits biofilm formation by multidrug resistant bacteria
Autores:Danielle Trentin (PPGCF - UFRGS - PPGCF - Universidade Federal do Rio Grande do Sul / UFRGS - Universidade Federal do Rio Grande do Sul) ; Fernando Bonatto (UFRGS - Universidade Federal do Rio Grande do Sul) ; Karine Zimmer (UFRGS - Universidade Federal do Rio Grande do Sul) ; Vanessa Ribeiro (PPGCF - UFRGS - PPGCF - Universidade Federal do Rio Grande do Sul) ; Ana Lúcia Antunes (PPGCF - UFRGS - PPGCF - Universidade Federal do Rio Grande do Sul) ; Afonso Luis Barth (PPGCF - UFRGS - PPGCF - Universidade Federal do Rio Grande do Sul / HCPA - Hospital de Clínicas de Porto Alegre) ; Gabriel Soares (UFRGS - Universidade Federal do Rio Grande do Sul) ; Cristano Krug (UFRGS - Universidade Federal do Rio Grande do Sul) ; Israel Baumvol (UFRGS - Universidade Federal do Rio Grande do Sul / UCS - Universidade de Caxias do Sul) ; Alexandre José Macedo (PPGCF - UFRGS - PPGCF - Universidade Federal do Rio Grande do Sul / UFRGS - Universidade Federal do Rio Grande do Sul)

Resumo

Planktonic bacteria that attach to a surface and grow as a biofilm are protected from killing by antimicrobials, contributing to the persistence of infections such as those associated with medical implanted devices. To avoid having to search for new biomaterials, management of bacterial adhesion through the control of surface properties of materials used in the manufacture of indwelling devices can be pursued. In the present work we modified polystyrene (PS) by plasma surface modification in a mixture of N2 and H2 gases and challenged seven bacteria that present remarkable resistance to antimicrobials (KPC-producing enterobacteriaceae and Staphylococcus spp. strains) with respect to biofilm formation, on the treated surfaces. PS surfaces were characterized by X-ray photoelectron spectroscopy and water contact angle measurements. Biofilm formation was evaluated by crystal violet assay and bacterial growth by OD600 measures and resazurin assay. Surface hydrophobicity of bacterial strains was determined using the microbial adhesion to hydrocarbon (MATH) test. Differences were analyzed by one-way ANOVA followed by the Tukey test (p ≤ 0.05). All bacteria studied developed biofilm on PS. Klebsiella pneumoniae demonstrated moderate capability, while the other strains presented a strong capability to form biofilm on PS. We observed up to 83% inhibition of biofilm development on treated PS, without biocidal effect. The biofilm formation was inhibited for all hydrophilic bacterial strains when surface nitrogen concentration was in excess of 8.8 at.%, which was equivalent to polar component of the surface energy above 15 mJ/m2. Such beneficial effect may be explained in terms of electrostatic repulsion, limiting adhesion of bacteria onto treated surfaces. Since the treatments do not kill the bacteria, resistance (observed in usual antibiotic therapies) should not develop and bacteria in planktonic lifestyle could be more sensitive to antimicrobials, reducing hospital caring costs. We presented herein a plasma surface modification which produces a much less adherent and non-biocidal material, being a suitable clean alternative for medical applications. ACKNOWLEDGMENTS: FAPERGS, MCTI/CNPq and NANOBIOTEC-Brasil from CAPES for fellowships and financial support.


Palavras-chave:  biofilm, KPC-producing enterobacteriaceae, MRSA, plasma surface modification, polystyrene