What is on that keyboard? Detecting hidden environmental reservoirs of Clostridium difficile during an outbreak associated with North American pulsed-field gel electrophoresis type 1 strains.

Background: Numerous studies have demonstrated that environmental surfaces in the rooms of patients with Clostridium difficile infection (CDI) are often contaminated with spores. However, less information is available regarding the frequency of contamination of environmental surfaces outside of CDI isolation rooms.

Methods: We performed a point-prevalence culture survey for C difficile in rooms of patients not in isolation for CDI, in physician and nurse work areas, and on portable equipment, including pulse oximetry devices, electrocardiogram machines, mobile computers, and medication distribution carts. Isolates were characterized by assessment of toxin production, polymerase chain reaction (PCR) ribotyping, and PCR for binary toxin genes.

Results: Of 105 nonisolation rooms, 17 (16%) were contaminated with toxin-producing C difficile, with the highest rate of contamination on the spinal cord injury unit (32%). Of 87 surfaces cultured outside of patient rooms, 20 (23%) were contaminated, including 9 of 29 (31%) in physician work areas, 1 of 10 (10%) in nurse work areas, and 9 of 43 (21%) portable pieces of equipment, including a pulse oximetry finger probe, medication carts, and bar code scanners on medication carts. Of 26 isolates subjected to typing, 19 (73%) matched ribotype patterns detected in stool samples from CDI patients and 13 (50%) were epidemic, binary toxin-positive strains.

Conclusion: In the context of a CDI outbreak, we found that environmental contamination was common in nonisolation rooms, in physician and nurse work areas, and on portable equipment. Further research is needed to determine whether contamination in these areas plays a significant role in transmission.