Co-carriage of Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis among three different age categories of children in Hungary

PLoS One. 2020 Feb 7;15(2):e0229021. doi: 10.1371/journal.pone.0229021. eCollection 2020.


Background: The nasopharynx can from time to time accommodate otherwise pathogenic bacteria. This phenomenon is called asymptomatic carriage. However, in case of decreased immunity, viral infection or any other enhancing factors, severe disease can develop. Our aim in this study was to survey the nasal carriage rates of four important respiratory pathogens in three different age groups of children attending nurseries, day-care centres and primary schools. This is the first study from Hungary about the asymptomatic carriage of H. influenzae and M. catarrhalis.

Methods: Altogether 580 asymptomatic children were screened in three Hungarian cities. Samples were collected from both nostrils with cotton swabs. The identification was based on both colony morphology and species-specific PCRs. Serotyping was performed for S. pneumoniae, H. influenzae and M. catarrhalis. Antibiotic susceptibility was determined with agar dilution, according to the EUCAST guidelines. Clonality was examined by PFGE.

Results and conclusions: Whereas the carriage rates of S. pneumoniae, H. influenzae and M. catarrhalis clearly decreased with age, that of S. aureus showed an opposite tendency. Multiple carriage was least prevalent if S. aureus was one of the participants. The negative association between this bacterium and the others was statistically significant. For pneumococcus, the overall carriage rate was lower compared to earlier years, and PCV13 serotypes were present in only 6.2% of the children. The majority of H. influenzae isolates was non-typeable and no type b was detected; serotype A was dominant among M. catarrhalis. All four bacteria were more sensitive to antibiotics compared to clinical isolates. No MRSAs were detected, but we found three mupirocin resistant strains. The positive effect of Hib- and PCV-vaccination is undoubted. Continued surveillance of these pathogens is required.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Age Factors
  • Anti-Bacterial Agents / pharmacology
  • Carrier State / epidemiology*
  • Carrier State / microbiology*
  • Child
  • Child, Preschool
  • Coinfection / epidemiology
  • Coinfection / microbiology
  • Female
  • Haemophilus Infections / epidemiology
  • Haemophilus Infections / microbiology
  • Haemophilus influenzae* / classification
  • Haemophilus influenzae* / drug effects
  • Haemophilus influenzae* / genetics
  • Haemophilus influenzae* / isolation & purification
  • Humans
  • Hungary / epidemiology
  • Infant
  • Male
  • Microbial Sensitivity Tests
  • Moraxella catarrhalis* / classification
  • Moraxella catarrhalis* / drug effects
  • Moraxella catarrhalis* / genetics
  • Moraxella catarrhalis* / isolation & purification
  • Moraxellaceae Infections / epidemiology
  • Moraxellaceae Infections / microbiology
  • Nasopharynx / microbiology*
  • Pneumococcal Infections / epidemiology
  • Pneumococcal Infections / microbiology
  • Public Health Surveillance
  • Risk Factors
  • Serogroup
  • Staphylococcus aureus* / classification
  • Staphylococcus aureus* / drug effects
  • Staphylococcus aureus* / genetics
  • Staphylococcus aureus* / isolation & purification
  • Streptococcus pneumoniae* / classification
  • Streptococcus pneumoniae* / drug effects
  • Streptococcus pneumoniae* / genetics
  • Streptococcus pneumoniae* / isolation & purification


  • Anti-Bacterial Agents

Grants and funding

This work was supported by the National Research, Development and Innovation Office/Hungarian Scientific Research Fund [grant number K108631], awarded to O.D. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.