title: Clostridium difficile strain NAP-1 is not associated with severe disease in a nonepidemic setting.
abstract: OBJECTIVE
  Recent outbreaks of Clostridium difficile infection (CDI) in North America and in Europe with very high case-fatality rates have been associated with infection by North American Pulsed Field Type I (NAP-1) isolates. This study examined whether NAP-1 strains are associated with worse outcomes of CDI in a nonepidemic, nosocomial setting.
  
  
  METHODS
  All cases of CDI that occurred over a 13-month period at a tertiary medical center were examined for risk factors associated with increased severity of CDI and other outcomes. Stool samples from each patient were cultured for C difficile and the resulting isolates were strain-typed by pulsed-field gel electrophoresis.
  
  
  RESULTS
  Strain types were obtained from 236 of 272 CDI samples; the NAP-1 strain was identified in 59 (25%). In this inpatient cohort of patients with CDI, the incidence of in hospital death was 12.1% and of death caused by CDI was 4.0%. Of the patients with CDI, 22.1% met the combined outcome end point of severe CDI. In both univariate and multivariate analyses, patients infected with the NAP-1 strain did not have worse outcomes compared with those infected with non-NAP-1 strains. Infection with the NAP-1 strain was correlated with admission from outside health care facilities regardless of whether symptoms of CDI began before or after admission to the study hospital.
  
  
  CONCLUSIONS
  The NAP-1 strain of C difficile was found to cause 25% of cases of CDI in the hospital where the study was performed. However, compared with non-NAP-1 strains, CDI was not associated with increased severity of disease in this nonepidemic setting.
authors.affiliation: Division of Gastroenterology and Hepatology, University of Virginia Medical Center, Charlottesville, Virginia, USA. jwc5t@virginia.edu
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Cloud
authors.forename: Laura
authors.initials: L
authors.lastname: Noddin
authors.forename: Amanda
authors.initials: A
authors.lastname: Pressman
authors.forename: Mary
authors.initials: M
authors.lastname: Hu
authors.forename: Ciaran
authors.initials: C
authors.lastname: Kelly
mesh_terms: D000368:Aged; D015373:Bacterial Typing Techniques / Q000379:methods; D016360:Clostridioides difficile / Q000145:classification* / Q000302:isolation & purification*; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology*; D016172:DNA Fingerprinting / Q000379:methods; D016521:Electrophoresis, Gel, Pulsed-Field; D004761:Enterocolitis, Pseudomembranous / Q000453:epidemiology*; D005060:Europe; D005243:Feces / Q000382:microbiology; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D009656:North America; D015995:Prevalence; D012720:Severity of Illness Index