title: Interaction of live and dead Escherichia coli O157:H7 and fluorescent microspheres with lettuce tissue suggests bacterial processes do not mediate adherence.
abstract: OBJECTIVE
  The goal of this study was to determine whether any specific bacterial processes (biochemical or genetic) or cell surface moieties were required for the interaction between Escherichia coli O157:H7 and lettuce plant tissue.
  
  
  RESULTS
  Escherichia coli O157:H7 and Fluospheres (fluorescent polystyrene microspheres) were used in experiments to investigate interactions with lettuce. Fluospheres were used as they are a non-biological material, of similar size and shape to a bacterial cell, but lack bacterial cell surface moieties and the ability to respond genetically. Live and glutaraldehyde-killed E. coli O157:H7 attached at levels of c. 5.8 log(10) cells per cm(2) following immersion of lettuce pieces into a suspension containing c. 8 log(10) CFU ml(-1). In a separate experiment, numbers of bacteria or Fluospheres associated with lettuce decreased by c. 1.5 log cm(-2) following a 1-min wash. Exposure times of 1 min, 1 h, or 6 h had little effect on the level of attachment for Fluospheres, and live or killed cells of E. coli O157:H7 to lettuce tissue.
  
  
  CONCLUSIONS
  These results indicate that bacterial processes and cell surface moieties are not required for the initial interaction of E. coli O157:H7 to lettuce plant tissue.
authors.affiliation: Department of Food Science, Rutgers University, New Brunswick, NJ 08901, USA.
authors.forename: E B
authors.initials: EB
authors.lastname: Solomon
authors.forename: K R
authors.initials: KR
authors.lastname: Matthews
mesh_terms: D001422:Bacterial Adhesion / Q000502:physiology*; D001431:Bacteriological Techniques; D019453:Escherichia coli O157 / Q000737:chemistry / Q000378:metabolism*; D018545:Lactuca / Q000166:cytology*; D008863:Microspheres; D018515:Plant Leaves / Q000382:microbiology