title: Oropharyngeal and nasal Staphylococcus aureus carriage by healthy children.
abstract: BACKGROUND
  As healthy children are the main reservoir of respiratory pathogens and the main cause of bacterial diffusion in the community, it could be interesting to investigate the type of screening that should be used during the early years of life in order to obtain a more precise estimate of Staphylococcus aureus circulation. The aim of this study was to evaluate oropharyngeal and nasal S. aureus carriage in otherwise healthy children and adolescents aged 6-17 years.
  
  
  METHODS
  The oropharyngeal and nasal samples were collected in December 2013 from 497 healthy students attending five randomly selected schools in Milan, Italy, using an ESwab kit, and S. aureus was identified using the RIDA®GENE methicillin-resistant S. aureus (MRSA) system.
  
  
  RESULTS
  Two hundred and sixty-four subjects (53.1%) were identified as S. aureus carriers: 129 (25.9%) oropharyngeal carriers and 195 (39.2%) nasal carriers, of whom 60 (12.1%) were both oropharyngeal and nasal carriers. Oropharyngeal carriage increased with age (p < 0.001), whereas nasal carriage decreased. There was little or no agreement between oropharyngeal and nasal carriage in any of the age groups. MRSA was identified in only three cases (0.6%), always in nasal samples. There were no differences between the carriers and non-carriers in terms of the distribution of age, gender, ethnicity, the number of siblings in the household, exposure to passive smoking, previous clinical history, allergic sensitisation, or previous influenza, pneumococcal and meningococcal vaccinations. The frequency of male children was higher among the subjects with positive nasal and oropharyngeal swabs (66.7%) than among those with positive oropharyngeal swabs alone (46.4%; p = 0.02).
  
  
  CONCLUSIONS
  The oropharyngeal carriage of mainly methicillin-sensitive S. aureus is frequent in otherwise healthy children, including a relatively high proportion of those without nasal colonisation. These findings highlight the importance of adding throat to nasal screening when monitoring the circulation of S. aureus in the community.
authors.affiliation: Department of Pathophysiology and Transplantation, Pediatric Highly Intensive Care Unit, Università degli Studi di Milano, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Commenda 9, 20122, Milano, Italy. susanna.esposito@unimi.it.
authors.forename: Susanna
authors.initials: S
authors.lastname: Esposito
authors.affiliation: Department of Pathophysiology and Transplantation, Pediatric Highly Intensive Care Unit, Università degli Studi di Milano, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Commenda 9, 20122, Milano, Italy. terranova.leonardo@gmail.com.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Terranova
authors.affiliation: Department of Pathophysiology and Transplantation, Pediatric Highly Intensive Care Unit, Università degli Studi di Milano, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Commenda 9, 20122, Milano, Italy. alberto.zampiero@unimi.it.
authors.forename: Alberto
authors.initials: A
authors.lastname: Zampiero
authors.affiliation: Department of Pathophysiology and Transplantation, Pediatric Highly Intensive Care Unit, Università degli Studi di Milano, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Commenda 9, 20122, Milano, Italy. valentina.ierardi@hotmail.it.
authors.forename: Valentina
authors.initials: V
authors.lastname: Ierardi
authors.affiliation: Department of Pathophysiology and Transplantation, Pediatric Highly Intensive Care Unit, Università degli Studi di Milano, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Commenda 9, 20122, Milano, Italy. walterpeves@gmail.com.
authors.forename: Walter Peves
authors.initials: WP
authors.lastname: Rios
authors.affiliation: Department of Epidemiology, IRCCS Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy. claudio.pelucchi@marionegri.it.
authors.forename: Claudio
authors.initials: C
authors.lastname: Pelucchi
authors.affiliation: Department of Pathophysiology and Transplantation, Pediatric Highly Intensive Care Unit, Università degli Studi di Milano, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Commenda 9, 20122, Milano, Italy. nicola.principi@unimi.it.
authors.forename: Nicola
authors.initials: N
authors.lastname: Principi
mesh_terms: D000293:Adolescent; D058345:Asymptomatic Infections / Q000453:epidemiology; D002353:Carrier State / Q000453:epidemiology / Q000382:microbiology*; D002648:Child; D005191:Family Characteristics; D005260:Female; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000302:isolation & purification; D009666:Nose / Q000382:microbiology*; D009960:Oropharynx / Q000382:microbiology*; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000382:microbiology*; D012574:Schools / Q000706:statistics & numerical data; D013203:Staphylococcal Infections / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000302:isolation & purification*