title: Concentration of airborne Staphylococcus aureus (MRSA and MSSA), total bacteria, and endotoxins in pig farms.
abstract: Pigs are very often colonized by Staphylococcus aureus and transmission of such pig-associated S. aureus to humans can cause serious medical, hygiene, and economic problems. The transmission route of zoonotic pathogens colonizing farm animals to humans is not well established and bioaerosols could play an important role. The aim of this study was to assess the potential occupational risk of working with S. aureus-colonized pigs in Switzerland. We estimated the airborne contamination by S. aureus in 37 pig farms (20 nursery and 17 fattening units; 25 in summer, 12 in winter). Quantification of total airborne bacterial DNA, airborne Staphylococcus sp. DNA, fungi, and airborne endotoxins was also performed. In this experiment, the presence of cultivable airborne methicillin-resistant S. aureus (MRSA) CC398 in a pig farm in Switzerland was reported for the first time. Airborne methicillin-sensitive S. aureus (MSSA) was found in ~30% of farms. The average airborne concentration of DNA copy number of total bacteria and Staphylococcus sp. measured by quantitative polymerase chain reaction was very high, respectively reaching values of 75 (± 28) × 10(7) and 35 (± 9.8) × 10(5) copy numbers m(-3) in summer and 96 (± 19) × 10(8) and 40 (± 12) × 10(6) copy numbers m(-3) in winter. Total mean airborne concentrations of endotoxins (1298 units of endotoxin m(-3)) and fungi (5707 colony-forming units m(-3)) exceeded the Swiss recommended values and were higher in winter than in summer. In conclusion, Swiss pig farmers will have to tackle a new emerging occupational risk, which could also have a strong impact on public health. The need to inform pig farmers about biological occupational risks is therefore crucial.
authors.affiliation: Institut universitaire romand de Santé au Travail, (Institute for Work and Health), University of Lausanne and Geneva, rue du Bugnon 21, CH-1011 Lausanne, Switzerland.
authors.forename: Frederic G
authors.initials: FG
authors.lastname: Masclaux
authors.forename: Olga
authors.initials: O
authors.lastname: Sakwinska
authors.forename: Nicole
authors.initials: N
authors.lastname: Charrière
authors.forename: Eulalia
authors.initials: E
authors.lastname: Semaani
authors.forename: Anne
authors.initials: A
authors.lastname: Oppliger
mesh_terms: D000383:Agriculture; D000391:Air Microbiology; D000822:Animal Husbandry; D000818:Animals; D058491:Bacterial Load; D004731:Endotoxins / Q000032:analysis*; D006799:Housing, Animal; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D016273:Occupational Exposure / Q000517:prevention & control; D013211:Staphylococcus aureus / Q000302:isolation & purification; D013552:Swine / Q000382:microbiology*; D013557:Switzerland / Q000453:epidemiology
chemical_list: D004731:Endotoxins
keywords: MRSA CC398; airborne bacteria; bioaerosols; occupational health; quantitative PCR; swine confinement buildings