title: Decreased cure and increased recurrence rates for Clostridium difficile infection caused by the epidemic C. difficile BI strain.
abstract: BACKGROUND
  An epidemic strain of Clostridium difficile designated by restriction endonuclease analysis (REA) as group BI has caused multiple outbreaks of severe C. difficile infection (CDI). The treatment response of patients infected with this strain is uncertain.
  
  
  METHODS
  Clostridium difficile isolates were collected from 2 phase 3 clinical trials comparing fidaxomicin to vancomycin and typed using REA. Clinical cure and recurrence outcomes were analyzed by strain type of the infecting organism, BI and non-BI, using both univariate and multivariate analyses.
  
  
  RESULTS
  From 999 patients, 719 isolates were available for typing (356 fidaxomicin treated and 363 vancomycin treated). BI was the most common REA group (34% of isolates). Patients infected with BI had lower cure rates (86.6%; 214 of 247) than those infected with non-BI strains (94.3%; 445 of 472) (P < .001). The cure rate difference between the BI and non-BI patients was significant for both vancomycin (P = .02) and fidaxomicin (P = .007). BI patients had a recurrence rate of 27.4% (51 of 186), compared with a recurrence rate of 16.6% (66 of 397) in non-BI patients (P = .002). By multivariate analysis, BI infection was statistically significant as a risk factor for reduced cure (odds ratio [OR], 0.48; 95% confidence interval [CI], .27-.85; P = .030) and for increased recurrence (OR, 1.57; 95% CI, 1.01-2.45; P = .046).
  
  
  CONCLUSIONS
  The clinical cure rate of patients infected with the epidemic BI C. difficile strain is lower than the cure rate of those infected with non-BI strains whether treated with fidaxomicin or vancomycin. Similarly, the CDI recurrence rate is increased in patients with the BI strain compared with patients with other C. difficile strains.
authors.affiliation: Edward Hines Jr VA Hospital, Hines, Illinois, USA. laurica.petrella@va.gov
authors.forename: Laurica A
authors.initials: LA
authors.lastname: Petrella
authors.forename: Susan P
authors.initials: SP
authors.lastname: Sambol
authors.forename: Adam
authors.initials: A
authors.lastname: Cheknis
authors.forename: Kristin
authors.initials: K
authors.lastname: Nagaro
authors.forename: Yin
authors.initials: Y
authors.lastname: Kean
authors.forename: Pamela S
authors.initials: PS
authors.lastname: Sears
authors.forename: Farah
authors.initials: F
authors.lastname: Babakhani
authors.forename: Stuart
authors.initials: S
authors.lastname: Johnson
authors.forename: Dale N
authors.initials: DN
authors.lastname: Gerding
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000617:Aminoglycosides / Q000627:therapeutic use; D000900:Anti-Bacterial Agents; D016360:Clostridioides difficile / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D003015:Clostridium Infections / Q000188:drug therapy* / Q000453:epidemiology / Q000382:microbiology*; D004311:Double-Blind Method; D005260:Female; D000077732:Fidaxomicin; D006801:Humans; D008297:Male; D008875:Middle Aged; D058889:Molecular Typing; D012150:Polymorphism, Restriction Fragment Length; D000091402:Prohibitins; D012008:Recurrence; D016896:Treatment Outcome; D014640:Vancomycin / Q000627:therapeutic use
chemical_list: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; C000717331:PHB2 protein, human; D000091402:Prohibitins; D014640:Vancomycin; D000077732:Fidaxomicin