Comparison between nasal swabs and nasopharyngeal aspirates for, and effect of time in transit on, isolation of Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae, and Moraxella catarrhalis.

We assessed the impact of the use of nasal swabs or nasopharyngeal aspirates and the time from specimen collection to storage at -70 degrees C on bacterial isolation. Haemophilus influenzae was isolated significantly less often from swabs than from nasopharyngeal aspirates. Samples in transit for >3 days were half as likely to grow Streptococcus pneumoniae and H. influenzae as those in transit for < or =3 days. There was no statistically significant difference for either Moraxella catarrhalis or Staphylococcus aureus.