title: A rapid and highly sensitive protocol for the detection of Escherichia coli O157:H7 based on immunochromatography assay combined with the enrichment technique of immunomagnetic nanoparticles.
abstract: BACKGROUND
  Escherichia coli O157:H7 (E. coli O157:H7) is an important pathogenic bacterium that threatens human health. A rapid, simple, highly sensitive, and specific method for the detection of E. coli O157:H7 is necessary.
  
  
  METHODS
  In the present study, immunomagnetic nanoparticles (IMPs) were prepared with nanopure iron as the core, coated with E. coli O157:H7 polyclonal antibodies. These IMPs were used in combination with immunochromatographic assay (ICA) and used to establish highly sensitive and rapid kits (IMPs+ICA) to detect E. coli O157:H7. The kits were then used to detect E. coli O157:H7 in 150 food samples and were compared with conventional ICA to evaluate their efficacy.
  
  
  RESULTS
  The average diameter of IMPs was 56 nm and the amount of adsorbed antibodies was 106.0 μg/mg. The sensitivity of ICA and IMPs+ICA was 10(5) colony-forming units/mL and 10(3) CFUs/mL, respectively, for purified E. coli O157:H7 solution. The sensitivity of IMPs+ICA was increased by two orders, and its specificity was similar to ICA.
  
  
  CONCLUSIONS
  The kits have the potential to offer important social and economic benefits in the screening, monitoring, and control of food safety.
authors.affiliation: Clinical Medical Research Center, The Second Clinical Medical College (Shenzhen People's Hospital), Jinan University, Shenzhen, People's Republic of China.
authors.forename: Hui
authors.initials: H
authors.lastname: Qi
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zhong
authors.forename: Han-Xin
authors.initials: HX
authors.lastname: Zhou
authors.forename: Chun-Yan
authors.initials: CY
authors.lastname: Deng
authors.forename: Hai
authors.initials: H
authors.lastname: Zhu
authors.forename: Jin-Feng
authors.initials: JF
authors.lastname: Li
authors.forename: Xi-Li
authors.initials: XL
authors.lastname: Wang
authors.forename: Fu-Rong
authors.initials: FR
authors.lastname: Li
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000737:chemistry / Q000378:metabolism; D002417:Cattle; D002846:Chromatography, Affinity / Q000379:methods*; D015169:Colony Count, Microbial / Q000379:methods; D019453:Escherichia coli O157 / Q000145:classification / Q000302:isolation & purification* / Q000378:metabolism; D005516:Food Microbiology; D017979:Gold Colloid / Q000737:chemistry / Q000378:metabolism; D018189:Immunomagnetic Separation / Q000379:methods*; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D008460:Meat / Q000382:microbiology; D008892:Milk / Q000382:microbiology; D055550:Protein Stability; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012703:Serotyping / Q000379:methods
chemical_list: D000907:Antibodies, Bacterial; D017979:Gold Colloid; D058185:Magnetite Nanoparticles