322. Suboptimal Performance of Recommended Methods to Determine Efficacy of Post-Discharge Cleaning
Session: Poster Abstract Session: Assessing and Reducing Infection Risk
Friday, October 21, 2011
Room: Poster Hall B1
  • IDSA-PDC_final.pdf (560.1 kB)
  • Background: Used to assess the efficacy of hospital cleaning practices, microbiologic methods can be costly, labor-intensive and do not allow for immediate feedback.  The use of a fluorescing marker (FM) and measured levels of adenosine triphosphate (ATP) after post-discharge cleaning (PDC) are recommended alternative methods.  We sought to compare the relative accuracy of these methods, including a comparison with both usual practice of visual inspection and microbial culture.

    Methods: The study was conducted among a convenience sample of all patient rooms in 661-bed academic medical center.  The efficacy of PDC was assessed on 15 pre-selected high-touch surfaces using the following methods on adjacent sampling areas: 1 x 1 cm FM placed prior to room occupancy and evaluated subsequent to PDC; 2 x 2 inch area swabbed for ATP measurement; visual inspection for ≥1 of 5 elements of uncleanliness (hair, moisture, tape residue, dust or other contaminant); microbiologic culture of a 2 x 2 inch area with a pre-moistened cotton swab inoculated onto sheep blood agar (SBA) plate.  Unclean surfaces were defined as: FM assessed by ultraviolet light was intact or partially intact; ATP >250 reflective light units; visual inspection demonstrated any contaminant; SBA plate demonstrated >5 colony forming units (CFU) growth over the entire plate (aerobic colony count, ACC) after 24 hours incubation.

    Results: Thirteen rooms were included in the study, with 186 sampled surfaces tested by all methods.  Of these 186 surfaces, 105 (56%), 84 (45%), and 95 (51%) were not clean by FM, ATP, and visual inspection, respectively.  For only 5 of 15 (33%) surface types tested, ATP was more likely to be unclean than FM.  While 126 (68%) of surfaces had positive growth on SBA, only 57 (31%) had ACC >5 CFU.  FM, ATP, and visual inspection demonstrated discordant results with ACC for 51% (94/186), 45% (83/186), and 42% (78/186) of surfaces (p < 0.01 by McNemar’s test for all comparisons).

    Conclusion: There is significant discordance between non-microbiologic methods and bacterial culture when used to assess efficacy of PDC.  Neither FM nor ATP performed better than visual inspection when compared to ACC.

    Subject Category: N. Hospital-acquired and surgical infections, infection control, and health outcomes including general public health and health services research

    Graham Snyder, MD1, Katharine Leary2, Aleah Holyoak2, Bernadette Sullivan, RN MBA2 and Sharon B. Wright, MD MPH2, (1)Infectious Diseases, Beth Israel Deaconess Medical Center, Boston, MA, (2)Silverman Health Care Quality Institute, Beth Israel Deaconess Medical Center, Boston, MA


    G. Snyder, None

    K. Leary, None

    A. Holyoak, None

    B. Sullivan, None

    S. B. Wright, None

    Findings in the abstracts are embargoed until 12:01 a.m. EST Thursday, Oct. 20 with the exception of research findings presented at IDSA press conferences.