title: Increasing prevalence of nasal and rectal colonization with methicillin-resistant Staphylococcus aureus in children with cancer.
abstract: BACKGROUND
  Infections with methicillin-resistant Staphylococcus aureus (MRSA), in community-settings, especially with strains carrying the Panton-Valentine Leukocidin (PVL) genes, have increased markedly in recent years. Colonization with S. aureus is a risk factor for infection. However, there are few studies that examine colonization and infection with PVL-positive strains of MRSA in cancer patients.
  
  
  METHODS
  The epidemiology of colonization and infection with MRSA was studied in children with cancer during two time periods: 2000/2001 and 2006/2007. PVL genes were screened and spa typing performed on the isolates.
  
  
  RESULTS
  The prevalence of colonization with MRSA increased from 0.6% in 2000/2001 to 2.9% in 2006/2007 (P = 0.0003). MRSA colonization at admission was associated with infection (P < 0.0001; RR 38.32; 95% CI: 23.36-62.84). The prevalence of infection increased from 0.99% in 2000/2001 to 3.78% in 2006-2007 (P = 0.0002). Of the 32 colonized patients, 18 (56%) had infection. None of the 14 colonized but non-infected patients had dual colonization of nares and rectum, while 8 of the 18 infected patients had colonization of both of these sites (P = 0.004). Ten patients (31%) were colonized with PVL-positive strains. Patients colonized with PVL-positive strains were more likely to be colonized both in the nares and rectum (P = 0.005), and more likely to have infection (P = 0.001). Recurrent MRSA infections were seen in 22% of patients.
  
  
  CONCLUSIONS
  An increasing prevalence of colonization with MRSA was observed in children with cancer at our institution. Colonization with MRSA especially with PVL-positive strains was associated with infection.
authors.affiliation: Department of Oncology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105-3678, USA. ashok.srinivasan@stjude.org
authors.forename: Ashok
authors.initials: A
authors.lastname: Srinivasan
authors.forename: Steven E
authors.initials: SE
authors.lastname: Seifried
authors.forename: Liang
authors.initials: L
authors.lastname: Zhu
authors.forename: Deo K
authors.initials: DK
authors.lastname: Srivastava
authors.forename: Rosalie
authors.initials: R
authors.lastname: Perkins
authors.forename: Jerry L
authors.initials: JL
authors.lastname: Shenep
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Bankowski
authors.forename: Randall T
authors.initials: RT
authors.lastname: Hayden
mesh_terms: D001427:Bacterial Toxins / Q000378:metabolism; D002648:Child; D005098:Exotoxins / Q000378:metabolism; D005260:Female; D006801:Humans; D007956:Leukocidins / Q000378:metabolism; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects / Q000302:isolation & purification* / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D009369:Neoplasms / Q000382:microbiology*; D009666:Nose / Q000382:microbiology*; D012007:Rectum / Q000382:microbiology*; D013203:Staphylococcal Infections / Q000150:complications
chemical_list: D001427:Bacterial Toxins; D005098:Exotoxins; D007956:Leukocidins; C078284:Panton-Valentine leukocidin