title: Transmission through air as a possible route of exposure for MRSA.
abstract: Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) is highly prevalent in pigs and veal calves. The environment and air in pig and veal calf barns is often contaminated with LA-MRSA, and can act as a transmission source for humans. This study explores exposure-response relationships between sequence type 398 (ST398) MRSA air exposure level and nasal ST398 MRSA carriage in people working and/or living on farms. Samples and data were used from three longitudinal field studies in pig and veal calf farm populations. Samples consisted of nasal swabs from the human participants and electrostatic dust fall collectors capturing airborne settled dust in barns. In both multivariate and mutually adjusted analyses, a strong association was found between nasal ST398 MRSA carriage in people working in the barns for >20 h per week and MRSA air levels. In people working in the barns < 20 h per week there was a strong association between nasal carriage and number of working hours. Exposure to ST398 MRSA in barn air seems to be an important determinant for nasal carriage, especially in the highly exposed group of farmers, next to duration of contact with animals. Intervention measures should therefore probably also target reduction of ST398 MRSA air levels.
authors.affiliation: Division of Environmental Epidemiology, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands.
authors.forename: Marian E H
authors.initials: ME
authors.lastname: Bos
authors.affiliation: Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
authors.forename: Koen M
authors.initials: KM
authors.lastname: Verstappen
authors.affiliation: Laboratory for Medical Microbiology and Immunology, St. Elisabeth Hospital, Tilburg, The Netherlands.|Laboratory for Microbiology and Infection Control, Amphia Hospital, Breda, The Netherlands.
authors.forename: Brigitte A G L
authors.initials: BA
authors.lastname: van Cleef
authors.affiliation: Division of Environmental Epidemiology, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands.
authors.forename: Wietske
authors.initials: W
authors.lastname: Dohmen
authors.affiliation: Division of Environmental Epidemiology, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands.|Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Dorado-García
authors.affiliation: Division of Environmental Epidemiology, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands.
authors.forename: Haitske
authors.initials: H
authors.lastname: Graveland
authors.affiliation: Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
authors.forename: Birgitta
authors.initials: B
authors.lastname: Duim
authors.affiliation: Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.|Central Veterinary Institute of Wageningen UR, Lelystad, The Netherlands.
authors.forename: Jaap A
authors.initials: JA
authors.lastname: Wagenaar
authors.affiliation: Laboratory for Medical Microbiology and Immunology, St. Elisabeth Hospital, Tilburg, The Netherlands.|Laboratory for Microbiology and Infection Control, Amphia Hospital, Breda, The Netherlands.|Department of Medical Microbiology and Infection Control, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Jan A J W
authors.initials: JA
authors.lastname: Kluytmans
authors.affiliation: Division of Environmental Epidemiology, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands.
authors.forename: Dick J J
authors.initials: DJ
authors.lastname: Heederik
mesh_terms: D000391:Air Microbiology; D000818:Animals; D006801:Humans; D058751:Livestock / Q000382:microbiology; D055624:Methicillin-Resistant Staphylococcus aureus / Q000302:isolation & purification*; D013203:Staphylococcal Infections / Q000382:microbiology / Q000635:transmission*