Avaliação da ação de moléculas sinalizadoras produzidas por Pseudomonas aeruginosa na formação do biofilme multiespécie de Escherichia coli e Staphylococcus aureus em superfície de aço inoxidável

Abstract

In food industries, the very conditions of the processing environment favor bacterial adhesion and subsequent development of biofilms on surfaces, a fact aggravated by poor sanitation. Biofilms developed on food processing surfaces are a serious problem as they become a chronic source of contamination by pathogens. Thus, the objective of this work was to evaluate the action of signaling molecules produced by Pseudomonas aeruginosa on biofilm-forming bacteria, Escherichia coli and Staphylococcus aureus, on AISI 304 stainless steel surface, both in monospecies and multispecies, at temperatures of 25°C and 35°C for 24 h using Miller Hinton broth (MH) and meat exudate as substrates, simulating a common food residue in the meat processing environment. For this, strains of E. coli and S. aureus were activated and inoculated on eppendorfs containing steel coupons and substrates, and part of the substrate (30% and 60%) was replaced with viable cell free supernatant (SLCV) of P. aeruginosa. After incubation, for the biofilm quantification, the violet crystal staining method was used and the supernatant was read after discolouring with 95% ethanol in a spectrophotometer with a wavelength of 570 nm. The results showed that the meat exudate substrate favored the formation of mono- and multispecies biofilms when compared to the MH broth. The substitution of 30% of the substrate by the P. aeruginosa SLCV significantly reduced the density of the formed biofilm. When 60% of the substrate was replaced by the P. aeruginosa SLCV the reduction obtained was not as expressive, and at 35°C in the MH broth there was a favor in the formation of the biofilm formed in this percentage of SLCV. As conclusion, we have that the molecules produced by P. aeruginosa present in the SLCV influenced the formation of mono and multispecies biofilm of E. coli and S. aureus on stainless steel surface under the conditions evaluated, demonstrating great potential of research and application of these molecules In the fight against biofilm formation.