Distance matters when it comes to bacterial contamination in patient rooms, study finds
A novel modeling method demonstrated that, when it comes to identifying hot spots for bacterial contamination in patient hospital rooms, distance matters.
“We understood from prior research that wastewater sites are a reservoir for multidrug-resistant organisms (MDROs) in the health care environment. We wanted to understand more comprehensively how bacteria are deposited during health care and how MDRO populations persist in different niches,” Brendan J. Kelly, MD, MSCE, assistant professor of medicine and epidemiology and infectious diseases physician and molecular epidemiologist at the University of Pennsylvania Perelman School of Medicine, told Healio.
“We thought that by combining 16S rRNA gene sequencing and a comprehensive MDRO culture strategy, we could better define where bacteria are deposited and the microenvironments in which specific MDROs persist.”
Kelly and colleagues performed a prospective cohort study of 51 rooms at the Hospital of the University of Pennsylvania in which a patient with an eligible MDRO had stayed in the prior 30 days between Nov. 4, 2019, and March 12, 2020.
They systematically sampled three environmental zones in each room corresponding to distances from the patient’s bed. Near-patient surfaces included the bed railing, television remote control, nurse call button and overbed tray table. Surfaces that were an intermediate distance from the patient included the IV fluid pump control pad, supply cart keypad, and in-room computer keyboard and mouse. The third zone — considered distant from patients but close to wastewater sites — included the light switch, doorknob, toilet handle and seat, handles and basin of the bath and in-room sinks . They used 16S rRNA sequencing to define the environmental microbiome in a subset of samples from those sites.
Overall, the study demonstrated that the probability of detecting resistant gram-negative organisms — including Enterobacterales, Acinetobacter species and Pseudomonas species — increased with distance from the patient, whereas Clostridioides difficile and MRSA were more likely to be detected close to the patient and less likely to be found near wastewater sites.
Kelly called it a “striking finding” that gram-positive MDROs were more likely to be found near patient beds and gram-negative MDROs were more likely to be found far from patients and close to wastewater sites.
“We believe that environmental cleaning methods can be improved by better understanding how specific MDROs persist in association with specific features of the built environment,” Kelly said. “We hope that novel design approaches, informed by our findings, will help to prevent environmental MDRO persistence and reduce the risk of health care-associated infections.”