The influence of environmental factors on the planktonic growth and biofilm formation of Escherichia coli

Abstract

In this study, the effects of environmental factors (different media, temperature, pH, salt and sugar concentrations) on the planktonic growth, biofilm formation and formed biofilm of Escherichia coli KGPMF 16 and Escherichia coli KGPMF 17 were investigated. Tested bacteria were isolated from traditionally made cheese produced in Southeastern Serbia (Sokobanja region). The influence on planktonic growth, biofilm formation and formed biofilm was determined using spectrophotometric method. The limiting factors for the planktonic growth and biofilm formation were temperature of 4 °C and all tested concentrations of salt. The growth of tested bacteria was higher in media enriched with lactose than in media containing glucose. TSB was more congenial media to the planktonic growth of bacteria than MHB broth. None of the tested bacteria demonstrated the ability to form biofilm at 4 °C and 44 °C. Only E. coli KGPMF 17 showed ability to form biofilm in TSB at 37 °C. Different concentrations of salt, glucose and lactose exhibited inhibitory effect on biofilm formation, but all tested concentrations of lactose showed stimulating effect on formed biofilm of E. coli KGPMF 17. These results contribute to better understanding of the effects of environmental factors on the development of E. coli in cheese.

Keywords

• biofilm formation
• E. coli
• planktonic growth
• traditionally made cheese