title: Increased prevalence of Mycoplasma pneumoniae serological positivity in Chilean young children.
abstract: BACKGROUND
  Mycoplasma pneumoniae is a frequent cause of respiratory infections in school children and adolescents. Epidemiological suspicion is important, since there are no specific symptoms or signs to help in diagnosing infection caused by this agent.
  
  
  OBJECTIVE
  To determine the variation in prevalence over the last 10 years of M. pneumoniae IgM seropositivity according to age, particularly in pre-schoolers.
  
  
  METHODS
  The results of M. pneumoniae IgM serological testing between January 2004 and December 2013 were analysed. Variables such as gender and month and year of sample processing were studied according to age groups (<5, 5-18, 19-50, 51-70 and >70 years of age).
  
  
  RESULTS
  Of a total of 20,020 serological samples, 31.9% proved positive for M. pneumoniae. All age groups showed increases in percentage seropositivity over the last 10 years, although the most significant increase corresponded to the 5-18 years group (from 15.8% to 54%), followed by children <5 years of age (from 8.6% to 30%). Seropositivity was significantly higher in women in all age groups, except in those over 50 years of age.
  
  
  CONCLUSIONS
  Children under five years of age were the group with the second highest increase in seropositivity.
authors.affiliation: Division of Pediatrics, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: J
authors.initials: J
authors.lastname: Carcey
authors.affiliation: Microbiology Unit, Clinical Service Laboratories Red Salud Christus-UC, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: P
authors.initials: P
authors.lastname: Garcia
authors.affiliation: Division of Public Health, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: O
authors.initials: O
authors.lastname: Padilla
authors.affiliation: Division of Pediatrics, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile; Division of Public Health, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile. Electronic address: jacastro17@hotmail.com.
authors.forename: J A
authors.initials: JA
authors.lastname: Castro-Rodriguez
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000907:Antibodies, Bacterial / Q000097:blood; D002648:Child; D002675:Child, Preschool; D002677:Chile / Q000453:epidemiology; D005260:Female; D006801:Humans; D007075:Immunoglobulin M / Q000097:blood; D007223:Infant; D008297:Male; D008875:Middle Aged; D009177:Mycoplasma pneumoniae / Q000276:immunology*; D011019:Pneumonia, Mycoplasma / Q000175:diagnosis / Q000453:epidemiology*; D015995:Prevalence; D012698:Serologic Tests; D012737:Sex Factors; D013997:Time Factors
chemical_list: D000907:Antibodies, Bacterial; D007075:Immunoglobulin M
keywords: Children; Epidemiology; IgM; Latin America; Mycoplasma pneumonia; Pre-schoolers; Prevalence; Serology