title: Escherichia coli serotype O157:H7 retention on solid surfaces and peroxide resistance is enhanced by dual-strain biofilm formation.
abstract: In a previous study we showed that an Escherichia coli O157:H7 strain that was unable to form biofilm was retained in large numbers in dual-strain biofilms formed with an E. coli O-:H4 companion strain. In this study we tested additional companion strains for their ability to retain E. coli O157:H7 strain 0475s. Companion strains producing biofilm that withstood aggressive washes were able to significantly increase serotype O157:H7 retention. Dual-strain biofilms with certain companion strains retained higher percentages of strain 0475s, and that ability was independent of biofilm total cell numbers. Tests with additional non-biofilm-forming E. coli O157:H7 strains showed that enhancement by companion strains was not unique to strain 0475s. Experiments using an E. coli companion strain with deletions of various curli and cellulose genes indicated that dual-strain biofilm formation was dependent on companion strain properties. Strain 0475s was not able to generate biofilm or persist on plastic when grown in broth with a biofilm-forming companion and separated by a 0.2 microm porous membrane, indicating a requirement for intimate contact with the companion strain. When dual-strain biofilms and planktonic cells were challenged with 5% H(2)O(2), strain 0475 showed greater survival in biofilms with certain companion strains compared to the corresponding planktonic cells. The results of this study indicate that non-biofilm-forming E. coli O157:H7 strains are retained on solid surfaces associated with biofilms generated by companion strains. However, properties other than biofilm mass enable certain companion strains to retain greater numbers of E. coli O157:H7.
authors.affiliation: Microbial Food Safety Research Unit, Eastern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Wyndmoor, Pennsylvania 19038, USA. gaylen.uhlich@ars.usda.gov
authors.forename: Gaylen A
authors.initials: GA
authors.lastname: Uhlich
authors.forename: Donna P
authors.initials: DP
authors.lastname: Rogers
authors.forename: Derek A
authors.initials: DA
authors.lastname: Mosier
mesh_terms: D001412:Bacillus subtilis / Q000378:metabolism; D001422:Bacterial Adhesion / Q000187:drug effects*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D002482:Cellulose / Q000378:metabolism; D018920:Coculture Techniques; D015169:Colony Count, Microbial; D004202:Disinfectants / Q000494:pharmacology*; D004926:Escherichia coli / Q000378:metabolism; D019453:Escherichia coli O157 / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000235:genetics; D005516:Food Microbiology; D017353:Gene Deletion; D005898:Glass; D006090:Gram-Negative Bacteria / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D056265:Microbial Interactions / Q000235:genetics; D050296:Microbial Viability / Q000187:drug effects*; D010933:Plankton / Q000254:growth & development / Q000378:metabolism; D013499:Surface Properties
chemical_list: D001426:Bacterial Proteins; D004202:Disinfectants; D029968:Escherichia coli Proteins; C077481:Crl protein, Bacteria; D002482:Cellulose; D006861:Hydrogen Peroxide