Discussion The relocation to the new hospital building with 100% single-occupancy rooms with private bathrooms resulted in a significant reduction of environmental contamination with HRMO during the three-year follow-up period. We observed lower CFU counts up to three months after relocating, with fluctuating CFU counts after that moment. Two- and three years after relocating, during the COVID-19 pandemic, CFU counts in single-occupancy rooms were significantly lower compared to the multiple-occupancy rooms in the old hospital building. Our findings should be considered in the broader context of the relocation. Besides the transition to 100% single-occupancy rooms, the introduction of a final cleaning after discharge of a patient in the new building might be associated with the reduction in environmental contamination with HRMO. Such a final cleaning is, however, more feasible in a single-occupancy room compared to a multiple-occupancy room. A second explanation for the higher number of HRMO identified in the old building is the number of VIM-positive Pseudomonas aeruginosa (VIM-PA) that was identified. The presence of VIM-PA in the old building was known since 2010, as a long-lasting multi-ward outbreak with the ICU as most affected ward (15). A persistent presence of VIM-PA in the sink drains of the ICU was then identified, which is reflected by the results of our study (15-20). To contain this reservoir, a bundle of ‘water free’ patient care was introduced in the ICU in 2011 (20). This was discontinued in the ICU in the new building, although for bathing of patients pre-packed washcloths remained instead of water and soap. After relocating to the new hospital building, VIM-PA did not colonize the sink drains within the time frame of this study. All P. aeruginosa isolates identified in our study all belonged to the outbreak strain (ST111) (18). When we analyzed the difference in environmental contamination with HRMO between the old and the new hospital building without the VIM-PA strains, there were still significantly less HRMO identified in the new hospital building (P<0.001). Sinks and sink drains are known and important reservoirs for HRMO, and often play a role in outbreaks (21, 22). Where in the old building 89.8% of HRMO isolates were identified from sink plugs, in the new building, no HRMO were identified from this location. This difference cannot be explained by a change in material. In both the old and the new building, drains and drain plugs were made of stainless steel. When we exclude sink plugs from the comparison between the old hospital and the new hospital building, the difference in environmental contamination is no longer statistically significant (P=0.06), although this could also be explained by a lack of statistical power. However, for our hospital’s new building, the decision was made to keep sinks in the ICU patient rooms, as a facility for healthcare workers to wash their hands and arms in case of unexpected contact with body fluids of the patient, or for specific microorganisms that are less susceptible to alcoholbased hand rub. Thus, these potential reservoirs of HRMO were present in the new building, but over a period of three years of patient care, we showed that they did not emerge as reservoir for HRMO again. Overall, the contamination rates with HRMO in both hospital buildings were low, especially when compared to other studies, where they showed contamination of HRMO in up to 55% of rooms (7, 23-25). An important explanation for these low contamination rates is the 3 161 Environmental contamination with MDRO in single-occupancy rooms
RkJQdWJsaXNoZXIy MTk4NDMw