Reduction in nosocomial Clostridium difficile infection (CDI) rates after terminal hypochlorite room cleaning

Background: Environmental contamination plays an important role in the transmission of Clostridium difficile within hospitals. C. difficile spores are capable of living for extended periods on inanimate surfaces and can persist for long periods despite cleaning with standard quaternary ammonium-based detergents. Diluted hypochlorite (bleach) solution has been shown to be sporicidal.

Objective: To determine the effect of terminal hypochlorite room cleaning on nosocomial CDI rates.

Methods: We performed a prospective cohort study of terminal room cleaning of C. difficile patients' rooms after hospital discharge with 1:10 hypochlorite solution versus standard quaternary ammonium cleaning. The intervention was initiated on our CDI-most prevalent ward A and then extended sequentially to 2 additional wards B and C over an 18 month period. 18, 6 and 3 months respectively were available for analysis. CDI rates were compared to a 24 month pre-intervention period on wards A, B, C and all other wards where standard quaternary ammonium room cleaning was performed. There were no significant changes in other infection control measures throughout the hospital during the intervention period. Risk ratios and p-values were assessed by chi-square, Fisher's exact, Mantel-Haenszel testing as appropriate.

Results: After bleach intervention the incidence of CDI cases decreased on Ward A from 1.776 to 0.662/1000 patient-days (RR 0.373 [95% CI 0.18-0.71]; p<0.002) (figure). Reduction, albeit with limited follow-up, was noted on Ward B from 1.136 to 0.724/1000 patient-days (RR 0.637 [95% CI 0.24-1.71]; p=0.39); on Ward C from 6.009 to 0/1000 patient-days (RR 0 [95% CI 0.00-1.43]; p=0.13). The effect of bleach cleaning on the 3 wards combined reduced CDI 60% (RR_MH 0.396 [95% CI 0.22-0.67]; p<0.001). VRE acquisition rates during the 18 month intervention period were unaffected (p=0.680). Although rates of CDI did not change on non-bleached wards, process control analysis demonstrated an overall 44% decline in hospital wide CDI after the initiation of bleach cleaning (RR=0.560 [95% CI 0.42-0.75]; p<0.001).

Conclusions: Our study demonstrates terminal diluted hypochlorite (bleach) room cleaning of C. difficile patient rooms can significantly reduce hospital Clostridium difficile infection rates. This study confirms the effectiveness of this simple, inexpensive intervention and deserves further attention.