Objective: Determine the cleanliness of mobile medical equipment that nursing staff are responsible for cleaning.
Methods: During unannounced visits to all medical and surgical wards, rolling equipment units used to measure patients’ vital signs were sampled for cleanliness by using an ATP bioluminescence assay system. 300 ATP readings, expressed as relative light units (RLUs) were obtained from control buttons of the automatic blood pressure (BP) unit, BP cuff, electronic thermometer, machine handle, and pulse oximeter. Not all items were present on each mobile unit. In addition, moistened swabs were used to obtain 100 cultures of the same surfaces of the mobile units. Swabs were inoculated onto blood agar plates, MRSA selective agar and campylobacter agar, and aerobic colony counts and the presence of MRSA and VRE were determined. MRSA and VRE were identified using standard methods.
Results: Median (range) ATP readings (expressed as RLUs) and the proportion of items with ATP readings of less than the arbitrary cutoff point proposed for cleanliness (< 250 RLUs) for the 300 surfaces sampled were as follows:
Range of RLUs
% with < 250 RLU
14 - 1532
23 – 5340
Blood pressure cuff
58 – 6407
42 – 31877
59 - 27297
Median (range) aerobic colony counts for the various items were as follows: for 21 control buttons: 2 CFUs (0 – 226); 16 thermometers: 3 CFUs (0 – 22); 23 blood pressure cuffs: 2 CFUs (0 – too numerous to count [TNTC]); 19 machine handles: 5 CFUs (0 – TNTC); and 21 pulse oximeters: 53 CFUs (0 – 813). MRSA was recovered from only 2 control buttons, 1 thermometer, 1 blood pressure cuff, 1 machine handle and 1 pulse oximeter. VRE was not recovered from any of the 100 site sampled.Conclusions: ATP bioluminescence assays and aerobic colony counts revealed that mobile medical equipment that are supposed to be cleaned by nursing staff are often contaminated with organic material, as reflected by ATP assays, and may be contaminated with aerobic bacteria, despite recently developed hospital policies that clearly delineated nursing staff as being responsible for such items. Although this study was conducted in a single hospital, the findings suggest that periodic education of nurses and monitoring of their cleaning practices appear warranted.