Binary toxin and death after Clostridium difficile infection

Abstract

We compared 30-day case-fatality rates for patients infected with Clostridium difficile possessing genes for toxins A and B without binary toxin (n = 212) with rates for patients infected with C. difficile possessing genes for A, B, and binary toxin. The latter group comprised patients infected with strains of PCR ribotype 027 (CD027, n = 193) or non-027 (CD non-027, n = 72). Patients with binary toxin had higher case-fatality rates than patients without binary toxin, in univariate analysis (relative risk [RR] 1.8, 95% confidence interval [CI] 1.2-2.7) and multivariate analysis after adjustment for age, sex, and geographic region (RR 1.6, 95% CI 1.0-2.4). Similar case-fatality rates (27.8%, 28.0%) were observed for patients infected with CD027 or CD non-027. Binary toxin either is a marker for more virulent C. difficile strains or contributes directly to strain virulence. Efforts to control C. difficile infection should target all virulent strains irrespective of PCR ribotype.

Figure 1

Description of Clostridium difficile (CD) infections surveillance in Denmark, with the 4 groups of C. difficile–infected patients included in the study, week 1, 2008–week 22, 2009. SSI, Statens Serum Institut; R, resistance.

Figure 2

Kaplan Meier curves showing the probability of patient survival after diagnosis of Clostridium difficile infection according to the 4 different infection groups (log-rank test, p<0.001). Blue line, C. difficile PCR ribotype 027; black line, C. difficile PCR ribotype non-027; green line, C. difficile with toxins A and B without binary toxin; red line, C. difficile unselected strains not referred for typing.