title: Unexpected sequence types in livestock associated methicillin-resistant Staphylococcus aureus (MRSA): MRSA ST9 and a single locus variant of ST9 in pig farming in China.
abstract: In October 2008 nine farrow-to-finish pig farms were visited in Shuangliu County in Sichuan Province, China. One farm was empty for one month but not cleaned after depopulation. Dust samples were collected at each farm and analysed for the presence of methicillin-resistant Staphylococcus aureus (MRSA). Dust samples from four farms were also analysed for the presence of methicillin-susceptible S. aureus (MSSA). On 5/9 farms MRSA was isolated and on 2/4 farms MSSA was isolated. On two farms, including the empty farm, no MRSA or MSSA could be detected. All MRSA isolates (n=43) belonged to spa type t899. MSSA isolates belonged to spa type t899 (n=12) and spa type t034 (n=2). From 4/9 farms the MRSA isolates of spa type t899 were assigned to multilocus sequence type (MLST) ST9 whereas on one farm the MRSA spa type t899 isolates belonged to a single locus variant of MLST ST9 (ST1376). MSSA isolates with spa type t899 belonged to MLST ST9 and the MSSA with spa type t034 belonged to MLST ST398. This is the first report on MRSA in pig farms in China and the first time that MRSA ST9 and a single locus variant of ST9 are detected in pig farms. This study shows that livestock associated MRSA is not restricted to clonal lineage ST398 as found in Europe and Northern America in commercial pigs but that other MRSA lineages are able to spread in livestock as well. The study confirms that livestock may act as a reservoir for MRSA.
authors.affiliation: Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.165, 3508 TD Utrecht, The Netherlands. j.wagenaar@uu.nl
authors.forename: Jaap A
authors.initials: JA
authors.lastname: Wagenaar
authors.forename: Hua
authors.initials: H
authors.lastname: Yue
authors.forename: Jane
authors.initials: J
authors.lastname: Pritchard
authors.forename: Marian
authors.initials: M
authors.lastname: Broekhuizen-Stins
authors.forename: Xander
authors.initials: X
authors.lastname: Huijsdens
authors.forename: Dik J
authors.initials: DJ
authors.lastname: Mevius
authors.forename: Thijs
authors.initials: T
authors.lastname: Bosch
authors.forename: Engeline
authors.initials: E
authors.lastname: Van Duijkeren
mesh_terms: D000818:Animals; D000829:Animals, Domestic / Q000382:microbiology; D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D002353:Carrier State / Q000662:veterinary; D002681:China; D004197:Disease Reservoirs; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D046915:Penicillin-Binding Proteins; D013203:Staphylococcal Infections / Q000382:microbiology / Q000662:veterinary*; D034421:Sus scrofa / Q000382:microbiology*; D013553:Swine Diseases / Q000382:microbiology; D015047:Zoonoses
chemical_list: D001426:Bacterial Proteins; D046915:Penicillin-Binding Proteins; C487789:mecA protein, Staphylococcus aureus