title: Molecular characterization of the first community-acquired methicillin-resistant Staphylococcus aureus strains from Central Iran.
abstract: BACKGROUND
  Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) has spread throughout the world with varying regional incidences and different staphylococcal cassette chromosome mec (SCCmec) elements in different genetic backgrounds. No information is available on CA-MRSA in Iran. A cross-sectional study was carried out among healthy students to investigate: (1) the prevalence of CA-MRSA in Central Iran, (2) the molecular epidemiology of such CA-MRSA strains, (3) the antimicrobial resistance patterns of the strains, and (4) the distribution of virulence genes in these CA-MRSA strains.
  
  
  METHODS
  A total of 700 nasal swabs were collected and subjected to S. aureus and MRSA-specific isolation procedures. Antimicrobial resistance patterns were determined using the disk diffusion method, and molecular typing was carried out by multi-locus sequence typing (MLST), SCCmec typing, and Staphylococcus protein A (spa) typing for all CA-MRSA isolates. PCR was used to detect various virulence genes.
  
  
  RESULTS
  One hundred fifty-four S. aureus strains were isolated from the anterior nares of 700 healthy students. According to the US Centers for Disease Control and Prevention definitions for CA-MRSA, seven (4.5%) isolates were confirmed as CA-MRSA. CA-MRSA isolates belonged to SCCmec types IV (n = 6) and V (n = 1). The predominant spa-type among the CA-MRSA isolates was t790 (n = 3), with single t660, t084, and t325 isolates; one isolate was not typeable. The predominant sequence type was ST22, t790, SCCmec IV in three isolates, and the four other sequence types were ST25, ST859, ST14, and ST15.
  
  
  CONCLUSIONS
  Iranian CA-MRSA strains are genetically diverse with an elevated prevalence of t790/ST22 SCCmec IV isolates. These findings support the need for more effective infection control measures to reduce nasal carriage and prevent dissemination of CA-MRSA in Iran.
authors.affiliation: Student Research Committee, Arak University of Medical Sciences, Arak, Iran; Department of Medical Microbiology, Faculty of Medicine, Arak University of Medical Sciences, Arak, Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Japoni-Nejad
authors.forename: Mohsen
authors.initials: M
authors.lastname: Rezazadeh
authors.forename: Hamid
authors.initials: H
authors.lastname: Kazemian
authors.forename: Nasimeh
authors.initials: N
authors.lastname: Fardmousavi
authors.forename: Alex
authors.initials: A
authors.lastname: van Belkum
authors.forename: Ehsanollah
authors.initials: E
authors.lastname: Ghaznavi-Rad
mesh_terms: D000293:Adolescent; D000328:Adult; D017714:Community-Acquired Infections / Q000453:epidemiology / Q000382:microbiology*; D005260:Female; D006801:Humans; D007492:Iran / Q000453:epidemiology; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D058885:Multilocus Sequence Typing; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000382:microbiology*; D037521:Virulence Factors / Q000235:genetics; D055815:Young Adult
chemical_list: D037521:Virulence Factors
keywords: CA-MRSA; MLST; Virulence-associated genes; spa typing