Influence of the nutritional growth conditions on the formation of biofilms

Introduction: Biofilm formation is influenced by many factors and varies between strains. Each strain uses different strategies and expresses different genes to promote biofilm formation and adherence. These processes are dependent on the environmental resources available. For some strains, the ability to form or not form a biofilm is strongly dependent on the biofilm growth conditions, such as the availability of nutrients. Listeria monocytogenes, Salmonella spp., and Escherichia coli are pathogenic bacteria associated with biofilm formation. Biofilm formation promotes the development and spread of infections difficult to treat, and contributes to antimicrobial resistance, which is a current concern. Purpose: This study aimed to evaluate the biofilm formation of Listeria monocytogenes (two serotypes), Salmonella enterica (four serotypes) and Escherichia coli strains on the surface of polystyrene under different nutrient conditions. Discussion and conclusions: Although this technique shows variability in results across different replicates, it remains possible to verify that: For three L. monocytogenes strains tested (2542, 12MOB047, and 12MOB050), the growth medium had a significant effect on biofilm formation (p < 0.05) (Figure 1); For two S. enterica strains tested (Typhimurium ESB9 and Senftenberg 775W), the growth medium also had a significant effect on biofilm formation (p < 0.05) (Figure 2); In contrast, no significant differences were observed for the E. coli strains (Figure 3). In conclusion, the greatest biofilm production of L. monocytogenes strains occurred in richer nutrient conditions (TSB with 1% glucose), in contrast to S. enterica strains (TSB).