Complicated pneumococcal pneumonia with pleural effusion or empyema in the 13-valent pneumococcal conjugate vaccine era

Abstract

Aim: The aim was to analyze the epidemiological, microbiological and clinical characteristics of patients with complicated pneumococcal pneumonia with pleural effusion (PE) or empyema.

Method: Prospective study in three Catalan hospitals in persons aged <18 years diagnosed with complicated pneumonia with PE or empyema with isolation of Streptococcus pneumoniae in blood or pleural fluid by culture or real-time PCR between January 2012 and June 2016. Patients were divided into <2 years and 2-17 years age groups. Epidemiological, microbiological, and clinical data of patients were compared annually in both groups. PCV13 vaccination coverage increased from 48.2% in 2012 to 74.5% in 2015.

Results: We included 143 patients. The incidence of pneumococcal pneumonia was 6.83 cases × 10^-5 persons/year in cases with PE or empyema and 2.09 cases × 10^-5 person-years in cases without (rate ratio [RR]: 3.27; 2.25-4.86; P < 0.001). Empyema was more frequent than PE (79.7% vs 20.3%, P < 0.005). Of 143 cases studied, 93 (65.0%, P < 0.001) were diagnosed by real-time-PCR, 43 (30.1%) by culture and RT-PCR and 7 (4.9%) by culture only. PCV13 serotypes were more frequent in complicated than in uncomplicated pneumonia (116/142, 81.7% vs 27/45, 60.0%; P = 0.003), especially serotype 1 (41/142, 28.9% vs 6/45, 13.3%, P : 0.036). From 2012 to 2015 there was a significant reduction in serotype 1 (16/43, 37.2% vs 3/27, 11.1%, P = 0.026), and a trend to an increase in non-PCV13 serotypes (6/43, 14% vs 9/27, 33.3%, P = 0.054).

Conclusions: A directly proportional relationship was observed between the reduction in pneumonia complicated with PE or empyema and a significant reduction in PCV13 serotypes, especially serotype 1, coinciding with increased PCV13 coverage.

Keywords: PCV13; Streptococcus pneumoniae; empyema; pleural effusion; pneumonia.