The Etiology of Pneumonia From Analysis of Lung Aspirate and Pleural Fluid Samples: Findings From the Pneumonia Etiology Research for Child Health (PERCH) Study

Abstract

Background: An improved understanding of childhood pneumonia etiology is required to inform prevention and treatment strategies. Lung aspiration is the gold standard specimen for pneumonia diagnostics. We report findings from analyses of lung and pleural aspirates collected in the Pneumonia Etiology Research for Child Health (PERCH) study.

Methods: The PERCH study enrolled children aged 1-59 months hospitalized with World Health Organization-defined severe or very severe pneumonia in 7 countries in Africa and Asia. Percutaneous transthoracic lung aspiration (LA) and pleural fluid (PF) aspiration was performed on a sample of pneumonia cases with radiological consolidation and/or PF in 4 countries. Venous blood and nasopharyngeal/oropharyngeal swabs were collected from all cases. Multiplex quantitative polymerase chain reaction (PCR) and routine microbiologic culture were applied to clinical specimens.

Results: Of 44 LAs performed within 3 days of admission on 622 eligible cases, 13 (30%) had a pathogen identified by either culture (5/44) or by PCR (11/29). A pathogen was identified in 12/14 (86%) PF specimens tested by either culture (9/14) or PCR (9/11). Bacterial pathogens were identified more frequently than viruses. All but 1 of the cases with a virus identified were coinfected with bacterial pathogens. Streptococcus pneumoniae (9/44 [20%]) and Staphylococcus aureus (7/14 [50%]) were the predominant pathogens identified in LA and PF, respectively.

Conclusions: Bacterial pathogens predominated in this selected subgroup of PERCH participants drawn from those with radiological consolidation or PF, with S. pneumoniae and S. aureus the leading pathogens identified.

Keywords: lung aspirate; PERCH; etiology childhood; pleural fluid aspirate; pneumonia.

Figure 1.

Enrollment of lung aspiration cases (n = 44) in 4 Pneumonia Etiology Research for Child Health (PERCH) sites performing lung aspiration. ^aIncludes 2 cases the PERCH chest radiograph (CXR) reading panel determined to have normal CXR results and 2 cases the panel determined to have uninterpretable results. The decision to perform the procedure was made by the clinical team responsible for care of the patient, based on information available to it at the time of admission. ^bLung aspirates not performed due to procedure not yet initiated at site or eligible but not done. ^cIncludes 1 case that the PERCH CXR reading panel determined to have normal CXR results. ^dIncludes 1 case that the PERCH CXR reading panel determined to have normal CXR results, and 2 cases that the panel determined to have uninterpretable results. Abbreviations: CXR, chest radiograph; PCR, polymerase chain reaction.

Figure 2.

Enrollment of pleural fluid (PF) cases (n = 19) in the Pneumonia Etiology Research for Child Health (PERCH) study. ^aClinicians from The Gambia PERCH site reviewed all of the chest radiographs (CXRs) from those cases where ≥2 standardized readers indicated pleural effusion, or where the case had a PF specimen obtained. The cases confirmed to have presence of any PF on CXR by the clinical review team were considered confirmed by the adjudication process. See Supplementary Appendix for more details. ^bAn additional 3 PF samples were obtained but not captured here because the adjudication process determined that their radiograph did not have evidence of PF. Two were obtained from children with consolidation on CXR (sample collected on day of admission in 1 case and on day 3 postadmission in the other) and 1 with an uninterpretable radiograph (specimen collected on day 6 postadmission). Abbreviations: CXR, chest radiograph; PCR, polymerase chain reaction.