A Pilot Study of Persistence of Clostridium difficile Contamination After Terminal Disinfection with 10% Bleach

Background: Previous studies have shown that unsupervised housekeeping personnel are effective at decontaminating only 10-60% of sites in rooms deliberately contaminated with C. difficile (CD) spores.  

Objective: To determine if routine terminal cleaning of hospital rooms at UPMC Presbyterian was sufficient to eradicate CD from rooms of patients with known CD infection.

Methods: Four rooms were sampled following 10% bleach disinfection by housekeeping personnel after transfer or discharge of a known CD patient prior to occupancy by a new patient; housekeepers were unaware of the sampling.  For rooms 1, 2, and 4, 10 high-contact sites (BP cuff, monitor cables, IV pump/pole, bed rails/buttons, call bell, bedside table, patient chair, sink handles, toilet handle, toilet seat) were sampled using sterile gloves and aseptic technique with a single sterile 2x2 inch sterile cotton gauze pad moistened with 2 mL phosphate-buffered saline transferred after sampling to a 50 mL conical tube.  For room 3, the ten sites were subdivided into 5 groups. Tubes were transferred to the lab within 60 minutes of collection where 10 mL CCMB-TAL (Anaerobe Systems, Morgan Hill CA) was added to each tube.  Samples were transferred to an anaerobic chamber (Coy) and incubated for 72 hours at 37 °C.   Fermenting samples were subcultured to pre-reduced 5% sheep blood agar (BBL). C. difficile was identified by colony morphology and L-prolineaminopeptidase activity (PRO disc, Remel).  Isolates were confirmed as toxigenic using RT-PCR for tcdB  (Prodesse) using genomic DNA extracted using the nuclisens EasyMag™ platform (biomérieux).   

Results:  3/4 (75%) rooms sampled were positive for toxigenic C. difficile.  For the third room sampled, only 1/5 culture groups was positive (call bell).  Of the CD positive rooms, C. difficile stool isolates were available for genotyping from 2/3 patients.

Conclusions:  Persistence of room contamination with C. difficile was not uncommon in our study and has been previously reported. As bleach disinfectant is sporicidal, it appears that some high contact surfaces, such as the patient call bell which are contacted by patients, RN staff, and physicians for various functions, appear to be either missed or more difficult to disinfect. More effectiveness research is needed to improve the process of adequate disinfection in hospital rooms.