Understanding the Short-Term Dynamics of MRSA Between Patients and Their Immediate Environment

Abstract

Background: Methicillin-resistant Staphylococcus aureus (MRSA) colonization of patients and contamination of their immediate environmental surfaces is common in the acute care setting, but there is much to be learned about the dynamics of MRSA transmission over a short period of time. Methods: A prospective, observational time-motion qualitative study was conducted at 2 hospitals: 1 in Michigan (hospital 1) and 1 in Zurich, Switzerland (hospital 2)—between November 2018 and July 2019. Hospitalized patients with a MRSA infection or colonization were enrolled. Microbiologic cultures for MRSA were collected from patient nares, axilla, groin and hands and several high-touch surfaces in their room (bed controls, call button, tray table, etc) at the first visit, and patient hands and high-touch surfaces continued to be swabbed every 90 minutes over the course of 5 hours. Patient hands and environment were disinfected after each swabbing. Clinical data were collected from patient’s medical chart. Results: We recruited 10 MRSA colonized or infected patients for the study with 50 hours of observation and obtained 360 patient and environmental swabs. Most were women (7 of 10); the average age was 52.8 years (Table 1). At the first visit, 8 (80%) patients were MRSA-colonized (at 1 or more body sites) and 5 (50%) rooms were MRSA-contaminated (at 1 or more surfaces). Also, 6 patients (60%) had an active MRSA infection and were actively receiving an anti-MRSA agent (eg, Vancomycin). Among those 6 patients receiving an anti-MRSA agent, 4 patients (67%) and 2 rooms (33%) were contaminated at the first visit. Among those 4 patients not receiving an anti-MRSA agent, all 4 patients (100%) and 3 rooms (75%) were contaminated at the baseline visit. Acquisitions (ie, MRSA recovered from a site it was not previously recovered from) occurred on 3 of 7 patient hands (43%) and on 6 occasions in the room (among 5 patients), most commonly at the toilet seat (2 of 6 times). MRSA prevalence on patient and room surfaces for the 5 patients enrolled at hospital 2 are illustrated in Figure 1, which shows colonization of patient and contamination of environment as well as activities performed by the patient in between culturing. Conclusions: We evaluated transmission of MRSA over brief periods of time; our results show that transmission of MRSA depended on patient activity in the room. Furthermore, degree of patient colonization is reflected by environmental contamination and supports the notion of constant transmission of MRSA from patients to environment.Funding: NoneDisclosures: None