Shedding of methicillin-resistant Staphylococcus aureus and multidrug-resistant gram-negative bacilli during outpatient appointments and procedures outside hospital rooms

Abstract

Limited information is available on the frequency of and risk factors for shedding of health care-associated pathogens in settings outside patient rooms. We conducted a cohort study of hospitalized or recently discharged patients with methicillin-resistant Staphylococcus aureus (MRSA) (N = 39) or multidrug-resistant gram-negative bacilli (MDR-GNB) (N = 11) colonization to determine the frequency of environmental shedding during appointments outside hospital rooms or during outpatient clinic visits. Chi-square tests were performed to identify patient-level factors associated with environmental shedding. Spa typing was performed for environmental and nasal MRSA isolates. Of 50 patients enrolled, 39 were colonized with MRSA and 11 with MDR-GNB. Shedding during 1 or more appointments occurred more often for patients colonized with MRSA versus MDR-GNB (15 of 39, 38.5% versus 0 of 11, 0%; P = .02). The presence of a wound with a positive culture for MRSA was associated with shedding of MRSA during appointments (11 of 15, 73.3% with shedding versus 4 of 24, 16.7% with no shedding; P = .008). Eighty percent of environmental MRSA isolates were genetically related to concurrent nasal isolates based on spa typing. Environmental shedding of MRSA occurs frequently during appointments outside hospital rooms or during outpatient clinic visits. Decontamination of surfaces and strategies that reduce shedding of MRSA could reduce the risk for transmission in these settings.