Background: The carriage rate of pathogenic bacteria in the nasopharynx (NP) was determined using three separate techniques for obtaining samples.
Methods: The NP of 99 healthy adults was sampled with (1) nasal swab, (2) oral swab, and (3) nasal aspiration; 49 adults with common cold were sampled with an oral swab and nasal aspiration. Three selective agars were used to detect Streptococcus pneumoniae, Hemophilus influenzae, and Moraxella catarrhalis.
Results: Seventy-three percent of healthy adults and 74% of cold sufferers had at least one pathogen detected in the NP. Detection rates were 65% (oral NP swab), 38% (catheter aspiration), and 28% (nasal swab; p < 0.001). Carriage rates for S. pneumoniae, M. catarrhalis, and H. influenzae were 45, 33, and 30%, respectively. Both a nasal and an oral sample were required for optimal detection.
Conclusion: Bacterial pathogens were present in the NP of three-quarters of adults during wellness and during colds.