title: Molecular analysis of Staphylococcus epidermidis strains isolated from community and hospital environments in China.
abstract: BACKGROUND
  Staphylococcus epidermidis is a common cause of nosocomial infections worldwide. This study analyzed the differences in genetic endowment and clonal lineages with pathogenesis and resistance traits of S. epidermidis isolates collected from community and hospital environments (patients and healthcare staff) of the same ecological niche, time period, and geographical location in China.
  
  
  RESULTS
  Molecular epidemiology and population analysis showed that nasal colonization rates of S. epidermidis in the community of Shanghai area of China and in healthcare personnel were 44.8% (methicillin-resistant S. epidermidis, MRSE: 17.2%) and 61.3% (MRSE: 30.0%), respectively. 86.7% of clinical isolates were MRSE. Among the strains studied, 44 sequence types (STs) were identified with 91.7% belonging to clonal complex 2 (CC2). Only 40.8% isolates from patients were also found in healthy individuals. MRSE-ST2-SCCmecIII was the predominant clone in clinical isolates, almost resistant to all antibiotics tested. Biofilm-related genes IS256 and icaA were detected in majority of the predominant clinical MRSE-ST2 clone with a 40.5% biofilm-positive rate. No ST2 isolate was found in community setting. We found a high prevalence of arginine catabolic mobile element (ACME) (74.1%). The prevalence of ACME-arc and ACME-opp3 clusters was 71.6% and 32.4%, respectively. Methicillin-sensitive S. epidermidis (MSSE) isolates harbored more ACME (83.3%) than MRSE isolates (67.7%), and there was no association between ACME and SCCmec types. An association was found between low-level ACME presence and invasive infections.
  
  
  CONCLUSIONS
  We observed a high level of diversity within S. epidermidis in this study, with CC2 as the dominant clonal complex in both community and hospital settings. Only 40.8% of the isolates from patients were also found in healthy individuals. Contrary to that biofilm formation and multiple antibiotic resistance were associated closely with pathogenicity of S. epidermidis, ACME was more likely to be an indicator for colonization rather than a virulence factor.
authors.affiliation: Department of Laboratory Medicine, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Du
authors.forename: Yuanjun
authors.initials: Y
authors.lastname: Zhu
authors.forename: Yan
authors.initials: Y
authors.lastname: Song
authors.forename: Tianming
authors.initials: T
authors.lastname: Li
authors.forename: Tao
authors.initials: T
authors.lastname: Luo
authors.forename: Gang
authors.initials: G
authors.lastname: Sun
authors.forename: Chongguang
authors.initials: C
authors.lastname: Yang
authors.forename: Cuiming
authors.initials: C
authors.lastname: Cao
authors.forename: Yuan
authors.initials: Y
authors.lastname: Lu
authors.forename: Min
authors.initials: M
authors.lastname: Li
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D015373:Bacterial Typing Techniques; D018441:Biofilms / Q000187:drug effects / Q000254:growth & development; D002681:China / Q000453:epidemiology; D017714:Community-Acquired Infections / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology*; D003428:Cross Infection / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology*; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects / Q000235:genetics*; D005798:Genes, Bacterial; D006761:Hospitals; D006801:Humans; D010802:Phylogeny; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology*; D013212:Staphylococcus epidermidis / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D037521:Virulence Factors / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D037521:Virulence Factors