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MDROs transmitted ‘early, readily, and frequently’ between patient and room

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November 19, 2018

Study findings showed that multidrug-resistant organisms, or MDROs, are transmitted “early, readily, and frequently” between patients and hospital rooms, suggesting that terminal cleaning may be inadequate to prevent patients from getting infections from the environment, researchers reported in Infection Control & Hospital Epidemiology.

“We undertook this prospective multicenter study as a substudy of our large trial to characterize the nature of MDRO transmission between the environment and patients using a combination of standard microbiological and molecular techniques,” Deverick J. Anderson, MD, MPH, associate professor of medicine at Duke University School of Medicine, and colleagues wrote.

“The objective of this study was to determine whether, when, and in what direction epidemiologically important pathogens transfer between patients and surfaces within hospital rooms.”

The researchers recorded and described bacterial transfer events between patients and environmental surfaces at Duke University Hospital, a tertiary-care academic medical center with 921 beds, and Duke Regional Hospital, a community hospital with 250 beds. They assessed rooms that previously housed patients with one of four MDROs: MRSA, vancomycin-resistant enterococci (VRE), Clostridium difficile and multidrug-resistant Acinetobacter baumannii.

They collected microbiological samples from patients and environments upon admission into a newly disinfected inpatient room, then again on days 3 and 7 and for each week the patient remained in the room. They compared environmental organisms with organisms found in patient samples.

Among 80 patient-room admissions, Anderson and colleagues observed that 11.3% (n = 9) of patients were initially asymptomatically colonized with MDROs. And despite terminal disinfection, 55% (n = 44) of hospital room surfaces were contaminated with MDROs. There were 12 recorded microbiological bacterial transfer events to either the patient, the environment or both. Of those, 16% (n = 2) were associated with MRSA, 42% (n = 5) with VRE and 42% (n = 5) with C. difficile, they reported.

Overall, microbiological bacterial transfer events were recorded in 18.5% of patient encounters — 80% of them occurring within 3 days of admission regardless of the direction of transmission.

“If microbial transmission occurs early, readily, and frequently between patients and the environment, as shown in the study, [standard terminal cleaning] may be inadequate to prevent the acquisition of MDROs through the environment,” Anderson and colleagues wrote.

“Indeed, these results should compel us to develop new technologies and interventions to achieve safe continuous environmental disinfection within the health care setting. Future effort and research to reduce transmission of MDROs through the health care environment must improve upon the status quo approach to environmental disinfection.” – by Marley Ghizzone

Disclosures: The authors report no relevant financial disclosures.

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Hilary Babcock, MD

This study demonstrates the complexity of microbial transfer that can occur between patients and the environment. The study is unique in that researchers examined microbiological samples from the room and the patient to confirm the source of contamination between the patient and the environment. What is most striking is the early transmission of bacteria from the environment to patients. In some cases, however, typing revealed that although a type of bacteria found in the environment was subsequently found on the patient, it was not always the same strain. The findings have several implications. The transfer of bacteria is bidirectional. The environment remains a contaminated area, in which patients but also health care workers can pick up bacteria and potentially transfer them to other areas and patients, or both. Fortunately, in most sampled hospital admissions, microbial transfer events were not identified.  However, environmental cleaning practices still have room for improvement. More research and strong evidence-based procedures for daily as well as terminal room cleanings are needed. We also need to clearly define what is a “clean” surface to achieve safe disinfection in the healthcare environment.

Hilary Babcock, MD, MPH

President-elect, Society for Healthcare Epidemiology of America
Associate professor of medicine
Washington University School of Medicine

Disclosure: Babcock reports no relevant financial disclosures.