title: Prevalence and characterization of methicillin-resistant Staphylococcus aureus isolates from healthy university student athletes.
abstract: BACKGROUND
  The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) has been increasing in the general population, and there is concern that close or physical contact, such as in professional and collegiate sports, may increase spread of MRSA. We sought to determine the prevalence of MRSA colonization of male and female athletes from 9 different sports at a major, Division I University during a 12-week period, and determine the USA and SCCmec type from select isolates.
  
  
  METHODS
  Swabs for culture of MRSA were obtained from nasal, axillary, and inguinal sites from healthy, asymptomatic student athletes and support staff each week for 12 weeks. Select MRSA isolates were typed by pulsed field gel electrophoresis (PFGE), and the genes encoding for MecA, cassette chromosome recombinase (Ccr), and several toxins were determined by multiplex polymerase chain reaction (PCR). Discrepant results were clarified by multi-locus sequence typing (MLST) and spa typing.
  
  
  RESULTS
  Thirty-five percent (78/223) of test subjects were positive for MRSA during the study period, resulting in isolation of 139 MRSA isolates. However, 47% (37/78) of MRSA-positive participants carried MRSA in axillary or inguinal sites, but not in the anterior nares. There was significant correlation between MRSA carriage and participation in wrestling (76%, 19/25; adjusted odds ratio 29.7, 95% CI 5.8-151.5) and baseball (44%, 17/39; adjusted odds ratio 4.4, 95% CI 1.1- 17.4), compared with a staff prevalence of 18.1% (4/22), but other factors were not examined. Multiplex PCR analysis indicated that of the 32 isolates examined 26 could be typed, and all of these carried the SCCmec type IV cassette. PFGE typing identified USA types 300, 400, 500, 700, and 800. However, one isolate was not a known USA type, but was identified as a novel ST951 by MLST, and as spa type t216. Of the strains typed from the same individual, there was consistency, but also variation and alternation of the SCCmec and spa types isolated from individual subjects. Various staphylococcal toxin genes were identified in 31 of the 32 isolates analyzed.
  
  
  CONCLUSIONS
  Colonization by MRSA was greater in some student athletes than the average carriage rate for the general population, and only 53% of MRSA carriers were identified by nasal cultures. Carriage of MRSA clones on the same individual and transmission to contacts could vary over time, indicating colonization can be a dynamic process that may be difficult to control.
authors.affiliation: Virginia-Maryland Regional College of Veterinary Medicine, Blacksburg, VA, USA. annac@vt.edu.
authors.forename: Anna E
authors.initials: AE
authors.lastname: Champion
authors.affiliation: Edward Via Virginia College of Osteopathic Medicine, Blacksburg, VA, 24061, USA. tomgoodwindo@yahoo.com.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Goodwin
authors.affiliation: Edward Via Virginia College of Osteopathic Medicine, Blacksburg, VA, 24061, USA. pbrolins@vcom.vt.edu.
authors.forename: P Gunnar
authors.initials: PG
authors.lastname: Brolinson
authors.affiliation: Virginia-Maryland Regional College of Veterinary Medicine, Blacksburg, VA, USA. swerre@vt.edu.
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Werre
authors.affiliation: Virginia-Maryland Regional College of Veterinary Medicine, Blacksburg, VA, USA. rprater@vcom.vt.edu.|Edward Via Virginia College of Osteopathic Medicine, Blacksburg, VA, 24061, USA. rprater@vcom.vt.edu.
authors.forename: M Renee
authors.initials: MR
authors.lastname: Prater
authors.affiliation: Virginia-Maryland Regional College of Veterinary Medicine, Blacksburg, VA, USA. tinzana@vt.edu.|Virginia Tech Carilion School of Medicine, Virginia Polytechnic Institute and State University, Life Sciences 1, 970 Washington St. SW, Blacksburg, VA, 24061, USA. tinzana@vt.edu.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Inzana
mesh_terms: D000293:Adolescent; D056352:Athletes; D002353:Carrier State / Q000453:epidemiology* / Q000382:microbiology*; D004269:DNA, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D017720:Molecular Epidemiology; D058889:Molecular Typing; D060885:Multiplex Polymerase Chain Reaction; D009296:Nasal Cavity / Q000382:microbiology; D015995:Prevalence; D012867:Skin / Q000382:microbiology; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D013334:Students; D014481:United States / Q000453:epidemiology; D014495:Universities; D055815:Young Adult
chemical_list: D004269:DNA, Bacterial
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