Growth media and temperature effects on biofilm formation by serotype O157:H7 and non-O157 Shiga toxin-producing Escherichia coli.
Biofilm formation in most Escherichia coli strains is dependent on curli fimbriae and cellulose, and the production of both varies widely among pathogenic strains. Curli and cellulose production by colonies growing on agar are often identified by their affinity for Congo red dye (CR). However, media composition and incubation temperature can affect dye affinity and impose limitations on red phenotype detection by this method. In this study, we compared different Shiga toxin-producing E. coli for CR affinity and biofilm formation under different media/temperature conditions. We found strain and serotype differences in CR affinities and biofilm formation, as well as temperature and media requirements for maximum CR binding. We also constructed strains with deletions of curli and/or cellulose genes to determine their contributions to the phenotypes and identified two O45 strains with a medium-dependent induction of cellulose.
Molecular Characterization of Foodborne Pathogens Research Unit, Eastern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Wyndmoor, PA, USA.
Gaylen A
GA
Uhlich
Chin-Yi
CY
Chen
Bryan J
BJ
Cottrell
Ly-Huong
LH
Nguyen
D018441:Biofilms; D003470:Culture Media / Q000737:chemistry / Q000378:metabolism*; D019453:Escherichia coli O157 / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D054323:Shiga-Toxigenic Escherichia coli / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D013696:Temperature
D003470:Culture Media
Congo red; STEC; biofilm; serotype O157:H7; temperature regulation