Changes in the incidence and bacterial aetiology of paediatric parapneumonic pleural effusions/empyema in Germany, 2010-2017: a nationwide surveillance study

Abstract

Objectives: Parapneumonic pleural effusions/empyema (PPE/PE) are severe complications of community-acquired pneumonia. We investigated the bacterial aetiology and incidence of paediatric PPE/PE in Germany after the introduction of universal pneumococcal conjugate vaccine (PCV) immunization for infants.

Methods: Children <18 years of age hospitalized with pneumonia-associated PPE/PE necessitating pleural drainage or persisting >7 days were reported to the German Surveillance Unit for Rare Diseases in Childhood between October 2010 and June 2017. All bacteria detected in blood or pleural fluid (by culture/PCR) were included, with serotyping for Streptococcus pneumoniae.

Results: The median age of all 1447 PPE/PE patients was 5 years (interquartile range 3-10). In 488 of the 1447 children with PPE/PE (34%), 541 bacteria (>40 species) were detected. Aerobic gram-positive cocci accounted for 469 of 541 bacteria detected (87%); these were most frequently Streptococcus pneumoniae (41%), Streptococcus pyogenes (19%) and Staphylococcus aureus (6%). Serotype 3 accounted for 45% of 78 serotyped S. pneumoniae strains. Annual PPE/PE incidence varied between 14 (95%CI 12-16) and 18 (95%CI 16-21) PPE/PE per million children. Incidence of S. pneumoniae PPE/PE decreased from 3.5 (95%CI 2.5-4.6) per million children in 2010/11 to 1.5 (95%CI 0.9-2.4) in 2013/14 (p 0.002), followed by a re-increase to 2.2 (95%CI 1.5-3.2) by 2016/17 (p 0.205).

Conclusions: In the era of widespread PCV immunization, cases of paediatric PPE/PE were still caused mainly by S. pneumoniae and, increasingly, by S. pyogenes. The re-increase in the incidence of PPE/PE overall and in S. pneumoniae-associated PPE/PE indicates ongoing changes in the bacterial aetiology and requires further surveillance.

Keywords: Children; Parapneumonic pleural effusion; Pleural empyema; Pleural fluid; Streptococcus pneumoniae; Streptococcus pyogenes.