Carriage of respiratory tract pathogens and molecular epidemiology of Streptococcus pneumoniae colonization in healthy children attending day care centers in Lisbon, Portugal

Microb Drug Resist. 1999 Spring;5(1):19-29. doi: 10.1089/mdr.1999.5.19.


In an effort to establish the rate of carriage of antibiotic resistant respiratory pathogens in children attending urban day care centers (DCC) in Portugal, seven DCC in Lisbon were selected for determining the rate of nasopharyngeal colonization of children between the ages of 6 months to 6 years by Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. Of the 586 children studied between January and March 1996, 47% carried S. pneumoniae, 72% H. influenzae, and 54% M. catarrhalis. Twenty-four percent of the pneumococci had reduced susceptibility to penicillin, and most of these belonged to serogroups 19, 23, 14, and 6. An additional 19% were fully susceptible to penicillin but showed decreased susceptibility to other antimicrobials. These isolates expressed serogroups 6, 11, 14, 18, 19, and 34. The majority (96%) of M. catarrhalis and 20% of H. influenzae were penicillin resistant due to the production of beta-lactamases. Recent antimicrobial use was associated with carriage of penicillin non-susceptible pneumococci and beta-lactamase producing H. influenzae (p < 0.05). Individual DCC differed substantially from one another in their rates of carriage of antibiotic resistant H. influenzae and S. pneumoniae. Characterization of antibiotic resistant S. pneumoniae isolates by molecular fingerprinting techniques showed that each DCC had a unique microbiological profile, suggesting little, if any, exchange of the resistant microbial flora among them. An exception to this was the presence of isolates belonging to two internationally spread epidemic clones: the multiresistant Spanish/USA clone expressing serotype 23F, and the penicillin and sulfamethoxazole-trimethoprim resistant French/Spanish clone (serotype 14) which were detected in four and three DCC, respectively.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Carrier State / epidemiology*
  • Carrier State / microbiology
  • Child
  • Child Day Care Centers* / statistics & numerical data
  • Child, Preschool
  • Drug Resistance, Microbial
  • Drug Utilization
  • Electrophoresis, Gel, Pulsed-Field
  • Haemophilus influenzae / drug effects
  • Haemophilus influenzae / isolation & purification
  • Humans
  • Infant
  • Molecular Epidemiology
  • Moraxella catarrhalis / drug effects
  • Moraxella catarrhalis / isolation & purification
  • Nasopharynx / microbiology
  • Portugal / epidemiology
  • Respiratory Tract Infections / epidemiology*
  • Respiratory Tract Infections / microbiology
  • Serotyping
  • Streptococcus pneumoniae / drug effects
  • Streptococcus pneumoniae / genetics*
  • Streptococcus pneumoniae / isolation & purification


  • Anti-Bacterial Agents