title: Preliminary molecular epidemiology of the Staphylococcus aureus in lower respiratory tract infections: a multicenter study in China.
abstract: BACKGROUND
  Staphylococcus aureus (S. aureus) remains as an important microbial pathogen resulting in community and nosocomial acquired infections with significant morbidity and mortality. Few reports for S. aureus in lower respiratory tract infections (LRTIs) have been documented. The aim of this study was to explore the molecular epidemiology of S. aureus in LRTIs in China.
  
  
  METHODS
  A multicenter study of the molecular epidemiology of S. aureus in LRTIs was conducted in 21 hospitals in Beijing, Shanghai and twelve other provinces from November 2007 to February 2009. All the collected S. aureus strains were classified as minimum inhibitory concentration (MIC), mecA gene, virulence genes Panton-Valentine Leukocidin (PVL) and γ-hemolysin (hlg), staphylococcal cassette chromosome mec (SCCmec) type, agr type, and Multilocus Sequence Typing (MLST).
  
  
  RESULTS
  Totally, nine methicillin-sensitive S. aureus (MSSA) and 29 methicillin-resistant S. aureus (MRSA) strains were isolated after culture from a total of 2829 sputums or bronchoalveolar lavages. The majority of MRSA strains (22/29) had a MIC value of ≥ 512 µg/ml for cefoxitin. The mecA gene acting as the conservative gene was carried by all MRSA strains. PVL genes were detected in only one S. aureus strain (2.63%, 1/38). The hlg gene was detected in almost the all S. aureus (100% in MSSA and 96.56% in MRSA strains). About 75.86% of MRSA strains carried SCCmec III. Agr type 1 was predominant (78.95%) among the identified three agr types (agr types 1, 2, and 3). Totally, ten sequence type (ST) of S. aureus strains were detected. A new sequence type (ST1445) was found besides confirming ST239 as the major sequence type (60.53%). A dendrogram generated from our own MLST database showed all the bootstrap values ≤ 50%.
  
  
  CONCLUSIONS
  Our preliminary epidemiology data show SCCmec III, ST239 and agr type 1 of S. aureus as the predominant strains in LRTIs in Mainland of China.
authors.affiliation: Department of Respiratory and Critical Care Medicine, Peking University People's Hospital, Beijing 100044, China.
authors.forename: De-Zhi
authors.initials: DZ
authors.lastname: Li
authors.forename: Yu-Sheng
authors.initials: YS
authors.lastname: Chen
authors.forename: Jing-Ping
authors.initials: JP
authors.lastname: Yang
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Cheng-Ping
authors.initials: CP
authors.lastname: Hu
authors.forename: Jia-Shu
authors.initials: JS
authors.lastname: Li
authors.forename: Lan
authors.initials: L
authors.lastname: Mu
authors.forename: Ying-Hui
authors.initials: YH
authors.lastname: Hu
authors.forename: Rong
authors.initials: R
authors.lastname: Geng
authors.forename: Ke
authors.initials: K
authors.lastname: Hu
authors.forename: Shao-Xi
authors.initials: SX
authors.lastname: Cai
authors.forename: Huan-Ying
authors.initials: HY
authors.lastname: Wan
authors.forename: Qiu-Yue
authors.initials: QY
authors.lastname: Wang
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Wei
authors.forename: Juan
authors.initials: J
authors.lastname: DU
authors.forename: Qin
authors.initials: Q
authors.lastname: Yu
authors.forename: Xiao-Ning
authors.initials: XN
authors.lastname: Zhong
authors.forename: Rui-Qin
authors.initials: RQ
authors.lastname: Wang
authors.forename: Jian-Jun
authors.initials: JJ
authors.lastname: Ma
authors.forename: Gui-Zhen
authors.initials: GZ
authors.lastname: Tian
authors.forename: Si-Qin
authors.initials: SQ
authors.lastname: Wang
authors.forename: Zhan-Cheng
authors.initials: ZC
authors.lastname: Gao
mesh_terms: D000483:Alleles; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D002681:China / Q000453:epidemiology; D024881:Drug Resistance, Bacterial / Q000235:genetics; D006801:Humans; D008826:Microbial Sensitivity Tests; D011446:Prospective Studies; D012141:Respiratory Tract Infections / Q000453:epidemiology*; D013203:Staphylococcal Infections / Q000453:epidemiology*; D013211:Staphylococcus aureus / Q000187:drug effects / Q000472:pathogenicity*
chemical_list: D000900:Anti-Bacterial Agents