Purpose: The objective of this research is to determine if strains of each STEC serogroup can attach to stainless steel and potentially form biofilms.
Methods: Four strains for each serogroup with variation in presence of stx1 and stx2 and origin of strain were examined. Stainless steel hex nuts, with a rough or smooth surface, were incubated in either minimal or full nutrient broth inoculated with a single strain of STEC at 25°C up to 48 h. At the time interval (4, 8, 12, 24, or 48 h), the nut was removed, rinsed, stained with crystal violet, and the crystal violet was removed from the nut to determine solution absorbance at 590 nm to measure resultant biomass.
Results: Significant differences (P < 0.05) between strains within serogroup were found within the rough surface/minimal media combination for O45, O103 and O111 with some evidence of differences (P < 0.08) for O157 with no differences found over time. Significant differences between strains within serogroup were also found within the smooth surface/minimal media combination for O26, O45, O103, and O121 and no differences over time except for STEC O45 serogroup.
Significance: These data indicate differences in attachment ability between strains within serogroup. Further research utilizing strains with greater attachment abilities is needed to examine the effectiveness of commonly used detergents and sanitizing agents on STEC biofilm renewals as well as improvements of current methodologies to determine formation of STEC biofilms.