Are hygiene standards useful in assessing infection risk?

BackgroundWe monitored the surface level cleanliness in a 5-bed surgical intensive care unit (SICU) over a 10-week period to evaluate proposed hygiene standards.MethodsTen environmental sites within the SICU were sampled twice weekly, along with collection of clinical and patient activity data. The standards designate aerobic colony counts (ACCs) > 2.5 colony-forming units/cm2 from hand-touch sites and the presence of Staphylococcus aureus as indicating hygiene failure.ResultsNearly 25% of the 200 samples analyzed did not meet the standards, mostly from hand-touch sites on curtains, beds, and medical equipment. The total number of failures each week was associated with bed occupancy (P = .04), with a trend toward association with SICU-acquired infection (P = .11). Environmental S aureus was associated with the proportion of beds occupied (P = .02). Indistinguishable genotypes were found between patient and environmental staphylococci, with time scales supporting staphylococcal transmission in both directions.ConclusionsHygiene standards based on microbial growth levels and the presence of S aureus reflect patient activity and provide a means to risk-manage infection. They also expose a staphylococcal reservoir that could represent a more tangible risk to patients. Standards for surface level cleanliness merit further evaluation.