Frequently Touched Sites in the Intensive Care Unit Environment Returning 100 Colony-Forming Units per Surface Area Sampled Are Associated With Increased Risk of Major Bacterial Pathogen Detection

Background: A threshold for surface hygiene has not been defined for the healthcare arena. We aimed to identify the magnitude of bacterial contamination of frequently touched sites in the intensive care unit (ICU) environment that could be used to guide quality improvement initiatives. Methods: Nineteen patients in a mixed ICU environment (providing care for medical and surgical patients) were followed from admission for 72 hours in 2010. Baseline cultures of frequently touched environmental sites were obtained at time zero following active decontamination and at 12, 24, 48, and 72 hours without further disinfection. We tested for an association of environmental reservoirs returning ≥ 100 colony-forming units (CFU) per surface area sampled with major bacterial pathogen detection. Results: There were 446 ICU room, day, and reservoir combinations sampled from 19 patients. There were pathogens detected in 40% (79/199) of samples with ≥ 100 CFU vs. 14% (35/247) of samples returning < 100 CFU. The relative risk was 2.80 (95% CI: 1.97-3.98, P <0.0001). The odds ratio adjusted for time in hours was 3.11 (95% CI: 1.84-5.34, P < 0.0001). Conclusions: Frequently touched ICU environmental sites returning ≥ 100 CFU are associated with major bacterial pathogen detection. This threshold for surface hygiene can be used to ensure compliance with ICU environmental cleaning protocols and to guide quality improvement initiatives.