Validation of pleural fluid group A Streptococcus and Staphylococcus aureus PCR assays and their potential clinical impact in children with complicated pneumonia

Abstract

Background

Better diagnostic tools are needed to increase the yield and speed of pathogen identification in pediatric complicated community-acquired pneumonia (cCAP), and thereby, improve patient care through optimization of antibiotic therapy.

Methods

We performed analytical and clinical validations of a laboratory-developed group A Streptococcus (GAS) PCR and a commercially available Staphylococcus aureus (S. aureus), including methicillin-resistant S. aureus (MRSA), PCR for pleural fluid specimens and studied the potential clinical impact of pleural fluid GAS and S. aureus PCR testing in children with cCAP.

Results

Both assays demonstrated high analytical sensitivity, specificity, reproducibility, and accuracy in detection of their target pathogens in pleural fluid. In potential clinical impact analysis for 62 children with cCAP requiring pleural fluid drainage, the addition of GAS and S. aureus PCR testing to existing diagnostic testing increased pathogen yield from 71.0 % to 83.2 % (p = 0.023), decreased theoretical median time from hospitalization to optimal therapy from 5.1 days (95 % CI: 2.4–7.2) to 3.7 days (95 % CI: 1.9–6.9, p = 0.001) and theoretical median time from start to stop of unwarranted MRSA therapy from 1.5 days (95 % CI: 1.0–3.7) to 0.8 days (95 % CI: 0.5–1.2, p < 0.001).

Conclusion

PCR testing is a sensitive and specific method for detecting GAS and S. aureus in pleural fluid. Clinical implementation of these targeted pleural fluid PCR assays has the potential to significantly increase pathogen yield, facilitate faster de-escalation of MRSA therapy and transition to narrow, targeted antibiotics, suggesting their utility for pediatric complicated pneumonia.