title: Predicting recurrence of C. difficile colitis using bacterial virulence factors: binary toxin is the key.
abstract: BACKGROUND
  Recurrent Clostridium difficile colitis is common, yet the ability to predict recurrence is poorly developed.
  
  
  METHODS
  Patients ≥18 years of age treated at our institution for C. difficile of any severity were consecutively enrolled. C. difficile colitis was defined as symptoms of colitis with a positive PCR stool test. Each bacterial isolate was studied for virulence factors: tcdC mutations via PCR; the presence of genes for toxins A, B, and binary toxin using restriction fragment length polymorphism; and identification of ribotype 027 by PCR. Chi-squared tests, t tests, and logistic and linear regression were used to determine which virulence factors predicted recurrence.
  
  
  RESULTS
  Sixty-nine patients (male, 57 %) were studied, with a mean age of 64 ± 13 years. Twenty-one (30 %) patients were initially diagnosed as outpatients. There was no difference (p > 0.05) between virulence factors among inpatients and outpatients. The presence of a binary toxin gene was the single virulence factor independently associated with recurrence (p = 0.02). The combination of a tcdC mutation with binary toxin gene resulted in the highest odds of recurrence (OR, 5.3; 95 % CI, 3.52-6.09).
  
  
  CONCLUSIONS
  Binary toxin gene is a predictor of recurrent infection. Its presence may require longer antibiotic regimens in an effort to lower already elevated recurrence rates.
authors.affiliation: Department of Surgery, Penn State College of Medicine, 500 University Drive, H137, Hershey, PA 17033, USA. dstewart@hmc.psu.edu
authors.forename: David B
authors.initials: DB
authors.lastname: Stewart
authors.forename: Arthur
authors.initials: A
authors.lastname: Berg
authors.forename: John
authors.initials: J
authors.lastname: Hegarty
mesh_terms: D036002:ADP Ribose Transferases / Q000235:genetics*; D000368:Aged; D001426:Bacterial Proteins / Q000235:genetics*; D001427:Bacterial Toxins / Q000235:genetics*; D016360:Clostridioides difficile / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D003015:Clostridium Infections / Q000175:diagnosis / Q000382:microbiology*; D003092:Colitis / Q000175:diagnosis / Q000382:microbiology*; D004269:DNA, Bacterial; D004768:Enterotoxins / Q000235:genetics; D005260:Female; D005819:Genetic Markers; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012008:Recurrence; D012097:Repressor Proteins / Q000235:genetics; D021521:Ribotyping; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004269:DNA, Bacterial; D004768:Enterotoxins; D005819:Genetic Markers; D012097:Repressor Proteins; C105615:TcdC protein, Clostridium difficile; D037521:Virulence Factors; C041348:tcdA protein, Clostridium difficile; C031815:toxB protein, Clostridium difficile; D036002:ADP Ribose Transferases; C410164:actin-specific ADP-ribosyltransferase, Clostridium