Monitoring the effectiveness of cleaning in four British hospitals

Background: A survey of cleaning effectiveness was conducted in two wards in four acute hospitals in England and Wales. Surfaces were monitored immediately before and after cleaning on three separate occasions using visual assessment, adenosine triphosphate (ATP) bioluminescence, expressed in relative light units (RLUs), and microbiological methods (aerobic colony counts [ACC]), expressed in colony forming units (cfu) per cm(2). Methods: Comparison of data from a total of over 3000 assessments showed highly significant differences in failure rates between visual assessment and either ATP or microbiological counts. There was no significant difference in failure rates between ATP and microbiological counts. Using visual assessment, failure rates were significantly lower after cleaning than before. Using ATP or microbiological methods, failure rates were not significantly different after cleaning. Results: Data obtained using both ATP and ACC, indicated considerable variability after cleaning and that failed surfaces were often well in excess of benchmark values. Conclusions: Cumulatively the results indicate that visual assessment is not a reliable indicator of surface cleanliness or of cleaning efficacy. Concerns also arise about the standards of surface cleanliness achieved after cleaning in the hospitals.