title: Quality evaluation of LC-MS/MS-based E. coli H antigen typing (MS-H) through label-free quantitative data analysis in a clinical sample setup.
abstract: OBJECTIVE
  The need for rapid and accurate H typing is evident during Escherichia coli outbreak situations. This study explores the transition of MS-H, a method originally developed for rapid H antigen typing of E. coli using LC-MS/MS of flagella digest of reference strains and some clinical strains, to E. coli isolates in clinical scenario through quantitative analysis and method validation.
  
  
  METHODS
  Motile and nonmotile strains were examined in batches to simulate clinical sample scenario. Various LC-MS/MS batch run procedures and MS-H typing rules were compared and summarized through quantitative analysis of MS-H data output for a standard method development.
  
  
  RESULTS
  Label-free quantitative data analysis of MS-H typing was proven very useful for examining the quality of MS-H result and the effects of some sample carryovers from motile E. coli isolates. Based on this, a refined procedure and protein identification rule specific for clinical MS-H typing was established and validated.
  
  
  CONCLUSIONS
  With LC-MS/MS batch run procedure and database search parameter unique for E. coli MS-H typing, the standard procedure maintained high accuracy and specificity in clinical situations, and its potential to be used in a clinical setting was clearly established.
authors.affiliation: National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada; Department of Human Anatomy and Cell Sciences, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Keding
authors.initials: K
authors.lastname: Cheng
authors.forename: Angela
authors.initials: A
authors.lastname: Sloan
authors.forename: Stuart
authors.initials: S
authors.lastname: McCorrister
authors.forename: Lorea
authors.initials: L
authors.lastname: Peterson
authors.forename: Huixia
authors.initials: H
authors.lastname: Chui
authors.forename: Mike
authors.initials: M
authors.lastname: Drebot
authors.forename: Celine
authors.initials: C
authors.lastname: Nadon
authors.forename: J David
authors.initials: JD
authors.lastname: Knox
authors.forename: Gehua
authors.initials: G
authors.lastname: Wang
mesh_terms: D000942:Antigens, Bacterial / Q000032:analysis / Q000276:immunology*; D015373:Bacterial Typing Techniques / Q000379:methods; D002853:Chromatography, Liquid / Q000379:methods*; D004926:Escherichia coli / Q000145:classification / Q000276:immunology* / Q000502:physiology; D004927:Escherichia coli Infections / Q000382:microbiology; D005407:Flagella / Q000276:immunology / Q000378:metabolism / Q000502:physiology; D054884:Host-Pathogen Interactions; D006801:Humans; D040901:Proteomics / Q000379:methods; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D000942:Antigens, Bacterial; C022863:H antigen
keywords: E. coli; Flagella typing; LC-MS/MS; Mass spectrometry; Quality control