Evaluation of Pneumococcal Load in Blood by Polymerase Chain Reaction for the Diagnosis of Pneumococcal Pneumonia in Young Children in the PERCH Study
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Date
2017
Journal Title
Journal ISSN
Volume Title
Publisher
Clinical Infectious Diseases
Abstract
Detection of pneumococcus by lytA polymerase chain reaction (PCR) in blood had poor diagnostic accuracy for
diagnosing pneumococcal pneumonia in children in 9 African and Asian sites. We assessed the value of blood lytA quantification in
diagnosing pneumococcal pneumonia.
Methods. The Pneumonia Etiology Research for Child Health (PERCH) case-control study tested whole blood by PCR for
pneumococcus in children aged 1–59 months hospitalized with signs of pneumonia and in age–frequency matched community controls.
The distribution of load among PCR-positive participants was compared between microbiologically confirmed pneumococcal
pneumonia (MCPP) cases, cases confirmed for nonpneumococcal pathogens, nonconfirmed cases, and controls. Receiver operating
characteristic analyses determined the “optimal threshold” that distinguished MCPP cases from controls.
Results. Load was available for 290 of 291 cases with pneumococcal PCR detected in blood and 273 of 273 controls. Load was
higher in MCPP cases than controls (median, 4.0 × 103 vs 0.19 × 103 copies/mL), but overlapped substantially (range, 0.16–989.9 × 103
copies/mL and 0.01–551.9 × 103 copies/mL, respectively). The proportion with high load (≥2.2 log10 copies/mL) was 62.5% among
MCPP cases, 4.3% among nonconfirmed cases, 9.3% among cases confirmed for a nonpneumococcal pathogen, and 3.1% among
controls. Pneumococcal load in blood was not associated with respiratory tract illness in controls (P = .32). High blood pneumococcal
load was associated with alveolar consolidation on chest radiograph in nonconfirmed cases, and with high (>6.9 log10 copies/mL)
nasopharyngeal/oropharyngeal load and C-reactive protein ≥40 mg/L (both P < .01) in nonconfirmed cases but not controls.
Conclusions. Quantitative pneumococcal PCR in blood has limited diagnostic utility for identifying pneumococcal pneumonia
in individual children, but may be informative in epidemiological studies.
Description
Keywords
Pneumonia, Pneumococcus, PCR, Blood, Diagnosis
Citation
Deloria Knoll, M., Morpeth, S. C., Scott, J. A. G., Watson, N. L., Park, D. E., Baggett, H. C., ... & Mitchell, J. (2017). Evaluation of pneumococcal load in blood by polymerase chain reaction for the diagnosis of pneumococcal pneumonia in young children in the PERCH study. Clinical Infectious Diseases, 64(suppl_3), S357-S367. DOI: 10.1093/cid/cix149