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Title: Phenotypic and genotypic characterization of biofilm forming capability in non-O157 Shiga toxin-producing Escherichia coli strains
Authors: Chen C, Hofmann CS, Cottrell BJ, Strobaugh Jr TP, Paoli G, Nguyen LT, Yan X, Uhlich GA
Journal: PLoS One
Accepted date: 2013 Nov 20
Interpretive summary: Shiga toxin-producing Escherichia coli (STEC) are major food-safety pathogens in the United States and abroad. Serotype O157:H7 remains the most important STEC in many parts of the world but six other serogroups (O26, O145, O103, O121, O45, and O111) are also considered important. Bacteria growing on surfaces can encase themselves in a secreted polysaccharide matrix (biofilm formation) to increase their resistance to harsh environmental conditions. In the STEC, the role of biofilms in causing disease and promoting attachment to food processing surfaces remains in question because biofilm expression is sporadic in many strains and because of our general lack of knowledge regarding how and why biofilms are formed. We have shown previously that interruption of a biofilm regulatory gene by the insertion of a bacteriophage (virus that infects bacteria) and sporadic changes (mutations) in a second regulatory gene are responsible for limiting biofilm formation in serotype O157:H7. In this study we tested the six important non-O157 STEC, plus serogroup O113, for similar regulatory impediments. We found that non-O157 STEC were more likely to form biofilm than O157:H7 strains and bacteriophage insertions were less common than in serotype O157:H7. In addition, we found that lack of motility was also associated with biofilm failure in non-O157 strains. These results expand our knowledge of the mechanisms controlling biofilm formation in the major serogroups of STEC food-borne pathogens and will help identify control points for intervention strategies to reduce STEC persistence in the food production chain.
Publication date: 2013 Dec 27
Volume: 8
Issue: 12
Pages: e84863