Table 1: Biofilm formation after insulin addition in concentration of 2.5 U/mL for different incubation times.

Biofilm formation
E. coli Strain 0 h 6 h 12 h 18 h 24 h
24 h - +++ +++ +++ +++
Negative control-C1 - + ++ +++ +++
E. coli-C2 - +++ +++ +++ +++
Negative control-C2 - + ++ ++ +++
E. coli-C3 - +++ +++ +++ +++
Negative control-C3 - + + ++ +++
E. coli-Ref - + + + ++
Negative control-Ref - - - - -

(-) no biofilm; (+) weak biofilm; (++) moderate biofilm; (+++) strong biofilm.