Environmental contamination by carbapenem-resistant : The effects of room type and cleaning methods.

Objective: We evaluated environmental contamination by carbapenem-resistant Acinetobacter baumannii (CRAB), the effectiveness of cleaning practices, the performance of aerosolized hydrogen-peroxide (aHP) technology, and the correlation between measures of cleaning and environmental contamination.

Design: Serial testing of environmental contamination during a 7-month period.

Setting: Single-patient rooms in intensive care units (ICUs) and multipatient step-up and regular rooms in internal medicine wards in a tertiary-care hospital with endemic CRAB.

Methods: CRAB environmental contamination was determined semiquantitatively using sponge sampling.

Results: In step-up rooms, 91% of patient units (56% of objects) were contaminated, and half of them were heavily contaminated. In regular rooms, only 21% of patient units (3% of objects) were contaminated. In ICUs, 76% of single-patient rooms (24% of objects) were contaminated. Cleaning did not reduce the number of contaminated objects or patient units in step-up rooms. After refresher training, cleaning reduced the proportion of contaminated objects by 2-fold (P = .001), but almost all patient units remained contaminated. Using aerosolized hydrogen peroxide (aHP) disinfection after discharge of a known CRAB-carrier decreased room contamination by 78%, similar to the reduction achieved by manual hypochloride cleaning. Measuring cleaning efficacy using fluorescent gel did not correlate with recovery of CRAB by sponge cultures.

Conclusions: In step-up rooms, the high number of objects contaminated combined with poor efficacy of cleaning resulted in failure to eliminate CRAB in patient units. Fluorescent gel is a poor detector of CRAB contamination. The role of aHP is still unclear. However, its use in multipatient rooms is limited because it can only be used in unoccupied rooms.