Comparative study of Salmonella Typhimurium biofilms and their resistance depending on cellulose secretion and maturation temperatures

Abstract

We investigated the aspects of S. Typhimurium biofilms and their resistance (thermal and chemical) depending on the different morphotypes at room temperature (rdar; strain 43971 and bdar; strain 19585) and maturation temperature. Strain 19585 biofilm had a relatively low cell mass and polysaccharide content compared to strain 43971 in all cases, and when matured for 9 days at 15 °C, both properties were significantly higher than at 25 and 37 °C maturation. The difference in secretion ability influenced the pattern in which the biofilm increased resistance. The thermal and chemical resistance levels of strain 19585 biofilms increased at 15 °C, and those of strain 43971 biofilms increased at 15 and 25 °C. When the two strains were mixed, the aspect of biofilm formation was similar to that of strain 43971 except that the heat and chemical resistance were higher at 37 °C maturation. Following 9 days of biofilm maturation, we concluded that 15 °C compared with 25 and 37 °C was the optimal condition for rdar and bdar strains in terms of quantity of total cell mass, EPS secretions and resistance against heat and chemical treatments.