Microbiological yield from induced sputum compared to oropharyngeal swab in young children with cystic fibrosis

J Cyst Fibros. 2016 Sep;15(5):605-10. doi: 10.1016/j.jcf.2016.01.001. Epub 2016 Jan 26.


Background: Standard respiratory sampling in young children with cystic fibrosis (CF) is by oropharyngeal swab (OPS) as they cannot spontaneously expectorate. Sputum induction (IS) has been poorly investigated in this population. We aimed to compare the bacteriological yield of OPS vs. IS in young children with CF.

Methods: Sequentially paired OPS followed by IS samples was collected in children <5years of age attending a CF clinic in Cape Town, South Africa.

Results: IS was successfully paired with OPS in 98/113 (85%) attempts in 32 children (mean±SD 19±16months), with no serious adverse events. IS culture yield for any CF-associated bacteria from IS was 46% vs. 28% from OPS (p=0.01). The sensitivity, specificity, PPV and NPV of OPS compared to IS in isolating CF-associated bacteria were 56%, 96%, 93%, and 72% respectively.

Conclusion: Sputum induction is feasible, safe and superior to OPS for detecting CF-associated bacteria in young children with CF.

Keywords: Cystic fibrosis; Induced sputum; Oropharyngeal swab; Young children.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacteriological Techniques / methods*
  • Child, Preschool
  • Cystic Fibrosis* / diagnosis
  • Cystic Fibrosis* / epidemiology
  • Cystic Fibrosis* / microbiology
  • Feasibility Studies
  • Female
  • Humans
  • Infant
  • Male
  • Oropharynx / microbiology*
  • Reproducibility of Results
  • South Africa / epidemiology
  • Sputum / microbiology*