Abstract
BackgroundA better understanding of the epidemiology of nasopharyngeal carriage of Streptococcus pneumoniae is important to assess the impact of vaccination and the pathogenesis of pneumococcal disease. We compared the recovery of S. pneumoniae from nylon flocked, Dacron and rayon swabs.MethodsThe recovery of S. pneumoniae from mocked specimens using flocked, Dacron and rayon swabs were compared by culture. The yield from paired nasopharyngeal (NP) samples obtained from healthy children sampled with flocked and Dacron swabs was also determined using culture and lytA-targeted real-time polymerase chain reaction (qPCR).ResultsUsing mock specimen, the percentage recovery of S. pneumoniae ATCC 49619 (serotype 19F) strain from the flocked swabs was 100%, while it was 41% from Dacron swabs and 7% from rayon swabs. Similar results were observed for S. pneumoniae serotypes 1 and 5. S. pneumoniae was cultured from 18 of 42 (43%) paired NP samples from the healthy children (median age 8 [interquartile range (IQR) 5–16] months). The median number of colony-forming units (CFU) recovered from flocked swabs was two-fold higher (8.8×104 CFU/mL [IQR, 2.0×102 – 4.0×105 CFU/mL]) than Dacron swabs (3.7×104 CFU/mL [IQR, 4.0×102–3.2×105 CFU/mL], p = 0.17). Using lytA-targeted qPCR from paired NP samples, the median copy number of S. pneumoniae detected from flocked swabs was significantly higher than from Dacron swabs (3.0×105 genome copies/mL [IQR, 1.3×102−1.8×106] vs. 9.3×104 genome copies/mL [IQR, 7.0×101−1.1×106]; p = 0.005).ConclusionFlocked swabs released more S. pneumoniae compared to both Dacron and rayon swabs from mock specimens. Similarly, higher bacterial loads were detected by qPCR from flocked swabs compared with Dacron swabs from healthy children.
Highlights
Streptococcus pneumoniae is the leading bacterial cause of childhood pneumonia worldwide [1,2]
Analysis of variance was performed to determine whether the mean colony-forming units (CFU) of S. pneumoniae recovered was different within triplicates of each swab type or across S. pneumoniae strains when the experiments were repeated on three different days
There was no statistical differences in the mean CFU of S. pneumoniae recovered within triplicates of each swab type performed on the same day (p = 0.85) or when the experiments were repeated on three different days (p = 0.89), suggesting that the experiments were reproducible
Summary
Streptococcus pneumoniae is the leading bacterial cause of childhood pneumonia worldwide [1,2]. S. pneumoniae colonizes the nasopharynx of many healthy young children and only causes pneumonia in a small proportion of those colonized [3,4,5,6]. Since nasopharyngeal (NP) colonization by S. pneumoniae is key to understanding the pathogenesis of pneumococcal disease and is increasingly used as an endpoint for pneumococcal vaccine studies, it is important to establish the optimal strategy for recovery of S. pneumoniae from NP specimens. NP swabs are preferred as the procedure is simpler, quicker and better tolerated by children. A better understanding of the epidemiology of nasopharyngeal carriage of Streptococcus pneumoniae is important to assess the impact of vaccination and the pathogenesis of pneumococcal disease. We compared the recovery of S. pneumoniae from nylon flocked, Dacron and rayon swabs
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
