title: Prevalence of community-acquired methicillin-resistant Staphylococcus aureus and antibiotic resistance in patients with atopic dermatitis in Porto Alegre, Brazil.
abstract: BACKGROUND
  Atopic dermatitis (AD) is a skin manifestation of atopy caused by hyperreactivity to various antigens. Studies have shown that 60-100% of patients with this condition present with colonization by Staphylococcus aureus. Given increasing rates of antimicrobial resistance, the sensitivity to antimicrobials of S. aureus colonizing atopic patients has been investigated. Cross-sectional studies worldwide suggest that the prevalence of methicillin-resistant S. aureus infection (MRSA) in the AD population varies from 0% to 30.8%.
  
  
  OBJECTIVE
  The objectives of this study were to determinate the prevalence of S. aureus and MRSA in patients with AD in two dermatologic centers in Porto Alegre, Brazil.
  
  
  METHODS
  A total of 91 patients with AD attending two dermatologic centers in Porto Alegre were enrolled in this study from December 2009 to July 2011. Two skin swabs were taken from each patient, one from the nares and the other from a non-infected eczematous skin lesion. The swabs were sent to the laboratory, where standard procedures to isolate bacteria and identify S. aureus, antimicrobial resistance, and sensitivity patterns were carried out. The severity of AD was defined using the Eczema Area and Severity Index (EASI).
  
  
  RESULTS
  Of the 91 patients sampled, 67 (73.6%) patients were found to be positive for S. aureus colonization. Nasal swabs were positive in 55 (60.4%) patients, lesional swabs in 44 (48.4%) patients, and both lesional and nasal swabs were positive in 32 (35.2%) patients. Patients with positive swabs had a higher mean ± standard deviation EASI score [mean (9.1 ± 8.8)] compared with patients with negative swabs (3.9 ± 3.6) (P = 0.002). None of the 91 patients showed any evidence of MRSA infection. Overall, nearly 32% of the S. aureus isolated from nasal swabs and 36.40% of the S. aureus isolated from lesional swabs was resistant to erythromycin.
  
  
  CONCLUSIONS
  The results of this study confirm a high rate of S. aureus colonization in pediatric patients with AD and indicate a relevant association between colonization and high EASI score. No MRSA was found in cultures from this sample of patients in southern Brazil. Nearly one-third of isolates were identified as resistant to erythromycin, an antibiotic that is commonly used in pediatric patients.
authors.affiliation: Department of Dermatology, Federal University of Health Sciences of Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Petry
authors.forename: Caroline
authors.initials: C
authors.lastname: Lipnharski
authors.forename: Giancarlo R
authors.initials: GR
authors.lastname: Bessa
authors.forename: Vera B
authors.initials: VB
authors.lastname: Silveira
authors.forename: Magda B
authors.initials: MB
authors.lastname: Weber
authors.forename: Renan R
authors.initials: RR
authors.lastname: Bonamigo
authors.forename: Pedro A
authors.initials: PA
authors.lastname: d'Azevedo
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000704:Analysis of Variance; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001938:Brazil / Q000453:epidemiology; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D017714:Community-Acquired Infections / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology; D003430:Cross-Sectional Studies; D003876:Dermatitis, Atopic / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology*; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000302:isolation & purification*; D008826:Microbial Sensitivity Tests; D015995:Prevalence; D011446:Prospective Studies; D012720:Severity of Illness Index; D017678:Sex Distribution; D013207:Staphylococcal Skin Infections / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents