title: Detection of mixed populations of Clostridium difficile from symptomatic patients using capillary-based polymerase chain reaction ribotyping.
abstract: OBJECTIVE
  To investigate the simultaneous occurrence of more than 1 Clostridium difficile ribotype in patients' stool samples at the time of diagnostic testing.
  
  
  METHODS
  Stool samples submitted for diagnostic testing for the presence of toxigenic C. difficile were obtained for 102 unique patients. A total of 95 single colonies of C. difficile per stool sample were isolated on selective media, subcultured alongside negative (uninoculated) controls, and polymerase chain reaction (PCR) ribotyped using capillary gel electrophoresis.
  
  
  RESULTS
  Capillary-based PCR ribotyping was successful for 9,335 C. difficile isolates, yielding a median of 93 characterized isolates per stool sample (range, 69-95). More than 1 C. difficile ribotype was present in 16 of 102 (16%) C. difficile infection (CDI) cases; 2 of the 16 mixtures were composed of at least 3 ribotypes, while the remaining 14 were composed of at least 2.
  
  
  CONCLUSIONS
  Deep sampling of patient stool samples coupled with capillary-based PCR ribotyping identified a high rate of mixed CDI cases compared with previous estimates. Studies seeking to quantify the clinical significance of particular C. difficile ribotypes should account for mixed cases of disease.
authors.affiliation: Department of Internal Medicine, Division of Infectious Diseases, University of Michigan Health System, Ann Arbor, Michigan.
authors.forename: Adam A
authors.initials: AA
authors.lastname: Behroozian
authors.affiliation: Department of Internal Medicine, Division of Infectious Diseases, University of Michigan Health System, Ann Arbor, Michigan.
authors.forename: Jeffrey P
authors.initials: JP
authors.lastname: Chludzinski
authors.affiliation: Department of Internal Medicine, Division of Infectious Diseases, University of Michigan Health System, Ann Arbor, Michigan.
authors.forename: Eugene S
authors.initials: ES
authors.lastname: Lo
authors.affiliation: Department of Internal Medicine, Division of Infectious Diseases, University of Michigan Health System, Ann Arbor, Michigan.
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Ewing
authors.affiliation: Department of Internal Medicine, Division of Infectious Diseases, University of Michigan Health System, Ann Arbor, Michigan.
authors.forename: Sheila
authors.initials: S
authors.lastname: Waslawski
authors.affiliation: Clinical Microbiology Laboratories, Department of Pathology, University of Michigan Health System, Ann Arbor, Michigan.
authors.forename: Duane W
authors.initials: DW
authors.lastname: Newton
authors.affiliation: Department of Internal Medicine, Division of Infectious Diseases, University of Michigan Health System, Ann Arbor, Michigan.|Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan.
authors.forename: Vincent B
authors.initials: VB
authors.lastname: Young
authors.affiliation: Department of Internal Medicine, Division of Infectious Diseases, University of Michigan Health System, Ann Arbor, Michigan.|Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan.
authors.forename: David M
authors.initials: DM
authors.lastname: Aronoff
authors.affiliation: Department of Internal Medicine, Division of Infectious Diseases, University of Michigan Health System, Ann Arbor, Michigan.|Department of Microbiology, Montana State University, Bozeman, Montana.
authors.forename: Seth T
authors.initials: ST
authors.lastname: Walk
mesh_terms: D016360:Clostridioides difficile / Q000235:genetics*; D019075:Electrophoresis, Capillary / Q000379:methods; D004761:Enterocolitis, Pseudomembranous / Q000382:microbiology*; D005243:Feces / Q000382:microbiology; D005260:Female; D006801:Humans; D008297:Male; D016133:Polymerase Chain Reaction / Q000379:methods; D021521:Ribotyping / Q000379:methods
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