Preventing Multidrug-Resistant Spread in Healthcare Facilities

Antimicrobial resistance is a significant public health problem, particularly in healthcare facilities and nursing homes serving medically vulnerable patients. This threat may be exacerbated if facilities don’t have the ability to implement effective mitigation measures.

With this in mind, a team of informatics researchers at the Graduate School of Public Health and Health Policy at the City University of New York partnered with infectious disease researchers at the University of California-Irvine and UCLA Medical Center to simulate a variety of interventions designed to reduce the spread of multidrug-resistant organisms (MDROs) among healthcare facilities in Orange County, California. The study was published in JAMA Network Open.

The study’s authors employed an agent-based model to identify interventions and actions that were most effective in reducing or preventing the spread of methicillin-resistant Staphylococcus aureus (MRSA) and carbapenem-resistant Enterobacteriaceae (CRE) over a 3-year period from 2017 to 2020, based on a simulation of those microbes spreading in a group of healthcare facilities from 2010 to 2020.

Because healthcare facilities in a particular area often are interconnected, patients can easily carry MDROs from place to place, such as when they’re discharged from a hospital to a rehabilitation facility or nursing home. However, mitigation techniques have varying levels of success, and some facilities are constrained due to a lack of resources. Therefore, the authors felt it was imperative to pin down the interventions likely to yield the best results in terms of infection and transmission reduction.

The study focused on 42 facilities, including 18 hospitals, 3 long-term acute-care hospitals, and 21 nursing homes. Three specific interventions were modeled: increasing contact precaution effectiveness, meaning agents had a lower risk of contact with other agents residing in the same unit; boosting communication among facilities regarding MDRO status; and performing decolonization actions including bathing with antiseptic soap and swabbing nasal passages with iodine-based antiseptic solutions.

By increasing contact precaution effectiveness from the existing level of 40% to 48% for MRSA, the study’s authors were able to demonstrate a relative reduction in MRSA prevalence of 0.3%. A further increase in contact precaution effectiveness to 64% yielded a relative reduction in MRSA prevalence of 0.8%, or 761 fewer MRSA transmissions. At 48% contact precaution effectiveness, CRE prevalence was 0.8%; a 64% increase meant a relative reduction in CRE of 2.4%. This greater increase in contact precaution effectiveness translated to 166 fewer instances of CRE transmission.

The decolonization intervention offered the greatest reductions in MDRO transmission and prevalence, although the modeling study demonstrated different probabilities of clearing the colonization depending on the type of facility involved. In hospitals, the baseline probability was 39%, with a range of 24% to 54%. Long-term acute-care hospitals saw a clearance probability of 27%—somewhat lower than the rate for hospitals due to the higher likelihood of patient comorbidities as well as reliance on ventilators and indwelling devices such as tubes and catheters. The lowest clearance probability, 3%, was found in nursing homes, likely due to comorbidities, indwelling devices, and less frequent instances of bathing.

The intervention that yielded no change in MDRO prevalence or transmission rate was increasing communication among facilities.

Decolonization procedures offer the greatest bang for the buck, the authors conclude. While the study revealed that reduced MDRO transmission and prevalence did not become apparent until 6 months had passed, the benefits of these procedures became more apparent with time. While contact precautions did demonstrate some benefit, their uptake may be hampered in certain circumstances by facility guidelines that allow the implementation of precautions only in cases of active infection rather than colonization. Similarly, the inability to readily access patient MDRO status during a facility transfer can render interfacility communication essentially useless in this regard.

The authors point out that MDRO infections can result in significant expenses that far exceed the costs of the interventions used to prevent them. Simple steps such as using antimicrobial wipes and baths, donning gloves and gowns, and creating materials designed to raise awareness of MDROs among staff ultimately can be money-saving actions.