title: Molecular epidemiology and characteristic of virulence gene of community-acquired and hospital-acquired methicillin-resistant Staphylococcus aureus isolates in Sun Yat-sen Memorial hospital, Guangzhou, Southern China.
abstract: Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of both hospital and community infections globally. It's important to illuminate the differences between community-acquired MRSA (CA-MRSA) and hospital-acquired MRSA (HA-MRSA), but there have been confusions on the definition, especially for the MRSA isolates identified within 48 h of admission. This study aimed to determine the molecular characteristics and virulence genes profile of CA and HA-MRSA isolates identified less than 48 h after hospital admission in our region.
  
  
  
  A total 62 MRSA isolates identified within 48 h after admission and the clinical data were collected. Antimicrobial susceptibility test (AST) of collected isolates were performed according to the guidelines of Clinical and Laboratory Standards Institute (CLSI) 2015, and staphylococcal cassette chromosome mec (SCCmec) typing, multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE) and virulence gene profiling were performed to explore the molecular diversity.
  
  
  
  SCCmec III and sequence type (ST) 239 were the most prevalent SCCmec type and ST in both CA and HA-MRSA groups. HA-MRSA group had higher prevalence of SCCmec III (87.2 %) and ST239 (79.5 %) compared with CA-MRSA (60.9 and 43.4 %, both P < 0.001), while the frequency of SCCmec IV (26.0 %) and ST59 (21.7 %) were higher in CA-MRSA than its counterpart (P < 0.001 and P = 0.003). MRSA-ST239-III was the predominant type in this study (61.3 %, 38/62), especially in HA-MRSA group (76.9 %, 30/39). However, CA-MRSA strains exhibited more diversity in genotypes in this study. Meanwhile, CA-MRSA tended to have lower resistant percentage to non-β-lactams antibiotics but more virulence genes carriage, especially the staphylococcal enterotoxins (SE) genes. Notably, seb gene was only detected in CA-MRSA isolates (52.2 %), likely a significant marker for CA-MRSA isolates. Panton-Valentine leukocidin gene (PVL) was highly detected in both groups, while appeared no significantly different between CA-MRSA (47.8 %) and HA-MRSA (43.6 %).
  
  
  
  Our findings support a difference in the molecular epidemiology and virulence genes profile of CA-MRSA and HA-MRSA. Furthermore, this study indicates a possible transmission from HA-MRSA to CA-MRSA, which may cause the overlap of the definition.
authors.affiliation: Department of Laboratory, Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Xie
authors.affiliation: Department of Laboratory, Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.
authors.forename: Yunwen
authors.initials: Y
authors.lastname: Bao
authors.affiliation: Department of Gynaecology and Obstetrics, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.
authors.forename: Nengyong
authors.initials: N
authors.lastname: Ouyang
authors.affiliation: Department of Laboratory, Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.
authors.forename: Xinlu
authors.initials: X
authors.lastname: Dai
authors.affiliation: Department of Laboratory, Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.
authors.forename: Kunyi
authors.initials: K
authors.lastname: Pan
authors.affiliation: Department of Laboratory, Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.
authors.forename: Baiji
authors.initials: B
authors.lastname: Chen
authors.affiliation: Department of Laboratory, Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.
authors.forename: Yawen
authors.initials: Y
authors.lastname: Deng
authors.affiliation: Department of Laboratory, Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.
authors.forename: Xiquan
authors.initials: X
authors.lastname: Wu
authors.affiliation: Department of Laboratory, Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.
authors.forename: Fengqin
authors.initials: F
authors.lastname: Xu
authors.affiliation: Department of Laboratory, Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China. lehyu@126.com.
authors.forename: Hongyu
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Laboratory, Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China. hsongyin@126.com.
authors.forename: Songyin
authors.initials: S
authors.lastname: Huang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002681:China / Q000453:epidemiology; D017714:Community-Acquired Infections / Q000453:epidemiology* / Q000382:microbiology*; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D006761:Hospitals; D006801:Humans; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000235:genetics* / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D017720:Molecular Epidemiology; D058885:Multilocus Sequence Typing; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000235:genetics*; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors / Q000235:genetics*; D055815:Young Adult
chemical_list: D037521:Virulence Factors
keywords: Antimicrobial susceptibility; Methicillin-resistant Staphylococcus aureus; Molecular characteristics; Virulence gene