title: A case-control study of community-associated Clostridium difficile infection.
abstract: OBJECTIVE
  The aim of this study was to determine the incidence of and risk factors for community-associated Clostridium difficile infection (CDI).
  
  
  METHODS
  Prospective surveillance of community-derived faecal samples for C. difficile cytotoxin, followed by a questionnaire-based case-control study in two distinct patient cohorts (one semi-rural and the other urban).
  
  
  RESULTS
  The proportion of randomly selected faecal samples positive for C. difficile cytotoxin was 2.1% in both patient cohorts (median ages 73 and 45 years for the urban and semi-rural cohorts, respectively). Exposure to antibiotics in the previous 4 weeks, particularly multiple agents (P < 0.001), aminopenicillins (P < 0.05) and oral cephalosporins (P < 0.05), was significantly more frequent among cases than controls. Hospitalization in the preceding 6 months was significantly associated with CDI (45% versus 23%; P = 0.022). However, almost half the cases had not received antibiotic therapy in the month before C. difficile detection, and approximately one-third neither had exposure to antibiotics nor recent hospitalization. Contact with infants aged < or =2 years was significantly associated with CDI (14% versus 2%; P = 0.02). Prior exposure to gastrointestinal-acting drugs (proton pump inhibitor, H2 antagonist or non-steroidal anti-inflammatory) was not significantly more common in CDI cases. C. difficile PCR ribotype 001 caused 60% and 13% of urban and semi-rural community-associated CDI cases, respectively.
  
  
  CONCLUSIONS
  Reliance on antibiotic history and age (> or =65 years) will contribute to missed diagnoses of community-associated CDI. Potential risk factors for community-associated CDI should be explored further to explain the large proportion of cases not linked to recent antibiotic therapy or hospitalization.
authors.affiliation: Department of Microbiology, Leeds Teaching Hospitals, Old Medical School, Leeds LS1 3EX, UK. mark.wilcox@leedsth.nhs.uk
authors.forename: M H
authors.initials: MH
authors.lastname: Wilcox
authors.forename: L
authors.initials: L
authors.lastname: Mooney
authors.forename: R
authors.initials: R
authors.lastname: Bendall
authors.forename: C D
authors.initials: CD
authors.lastname: Settle
authors.forename: W N
authors.initials: WN
authors.lastname: Fawley
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D015373:Bacterial Typing Techniques; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D016360:Clostridioides difficile / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D017714:Community-Acquired Infections / Q000453:epidemiology* / Q000382:microbiology*; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics; D004761:Enterocolitis, Pseudomembranous / Q000453:epidemiology* / Q000382:microbiology*; D005243:Feces / Q000382:microbiology; D005260:Female; D005838:Genotype; D006760:Hospitalization; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods; D011446:Prospective Studies; D012307:Risk Factors; D012424:Rural Population; D011795:Surveys and Questionnaires; D013997:Time Factors; D014505:Urban Population
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial