2210. Nasopharyngeal Detection of Streptococcus pneumoniae and Clinical Disease Severity in Children with Community-Acquired Pneumonia (CAP)

Background Streptococcus pneumoniae is the most common pyogenic bacteria associated with CAP in children, but the proportion of cases might be underestimated because of the low sensitivity of current standard diagnostic methods. Nasopharyngeal (NP) carriage of pneumococcus commonly precedes the development of pneumococcal pneumonia, and facilitates pneumococcus interactions with other respiratory pathogens and the host immune response. This study investigated the relationship between pneumococcal carriage and the severity of CAP in children. Methods We conducted a prospective, multicenter, observational study for CAP among previously healthy children aged 2 months through 18 years in six children’s hospitals in Ohio. Blood, pleural fluid, and NP swabs were collected for pathogen detection by culture and/or polymerase chain reaction (PCR). S. pneumoniae was quantified in NP swabs by real-time PCR. Patient management followed the standard of care in each study site. Results Among 441 children with radiologically confirmed CAP, 156 (35.4%) had no bacterial or viral pathogens identified as etiologic agents. NP pneumococcal carriage rate in this group was 34.6%. Children with CAP and pneumococcal carriage (53/156) were younger (5.9 vs. 9.6 years, P < 0.001) than those with no carriage (103/156). Median neutrophil counts and median procalcitonin concentrations were significantly higher in the pneumococcal carriage group (12,030 vs. 8,370 cells/mm3 and 1.0 vs. 0.5 mg/dl, respectively; P < 0.05 for both) than in the non-carriage group. Children with documented pneumococcal carriage received respiratory support more frequently (50.0% vs. 28.2%, p = 0.012) and had a longer duration of hospitalization (3.5 ± 3.8 vs. 2.1 ± 2.0 days, P = 0.026) than those without pneumococcal carriage. Age was not associated with any of the variables used to assess clinical disease severity. Conclusion Pneumococcal carriage was associated with higher inflammatory markers and greater clinical disease severity in children with CAP in whom no pathogens were identified by standard diagnostics. This suggests that NP carriage of pneumococcus in children with CAP may modulate the host immune response and possibly influence clinical disease severity. Disclosures Octavio Ramilo, MD, Bill & Melinda Gates Foundation: Research Grant; Janssen: Research Grant; Merck: Advisory Board; NIH: Research Grant; Ohio Children’s Hospital Association (OCHA): Research Grant; Pfizer: Advisory Board, Consultant, Lectures; Sanofi/Medimmune: Advisory Board.