Evolution of the distribution of Streptococcus pneumoniae serotypes isolated in pleural fluid in the Madrid Autonomous Community between the years 2007–2018

Abstract

Introduction

The aim of this study was to describe the distribution of Streptococcus pneumoniae serotypes in isolates from pleural fluid in the Madrid Autonomous Community between the years 2007–2018.

Methods

Invasive pneumococcal disease strains isolated during the period 2007–2018 were studied. The frequency of serotypes from pleural fluid was compared with that observed in other samples.

Results

A total of 6,115 pneumococcal invasive isolates were processed. Of them, 182 (3%) were isolated from pleural fluid. A total of 70.9% of isolates belonged to some of the following six serotypes: 1, 3, 19A, 8, 7F and 5. The serotypes 3 and 8 increased significantly from 9.6% to 30.8%, and from 5.3% to 20.5%, respectively, over the periods 2007−2010 to 2015−2018.

Conclusions

Pneumococcal serotypes 3 and 8 are currently significant causes of infection of pleural fluid in our region.

Resumen

Introducción

El objetivo de este estudio es describir la distribución de serotipos de Streptococcus pneumoniae en aislados de líquido pleural en la Comunidad de Madrid (CM) entre los años 2007–2018.

Métodos

Se estudiaron las cepas de episodios de enfermedad neumocócica invasora aisladas en la CM durante el periodo 2007–2018. La frecuencia de serotipos en líquido pleural se comparó con la observada en otras muestras.

Resultados

Se procesaron 6.115 cepas invasoras de neumococo. Ciento ochenta y dos (3%) se aislaron en muestras de líquido pleural. El 70,9% de los aislados pertenecía a alguno de los 6 siguientes serotipos: 1, 3, 19A, 8, 7F y 5. Los serotipos 3 y 8 aumentaron significativamente, pasando del 9,6% al 30,8%, y del 5,3% al 20,5%, respectivamente, entre los períodos 2007−2010 a 2015−2018.

Conclusión

Los serotipos 3 y 8 son actualmente causas importantes de infección del líquido pleural en nuestra área.

Introduction

Invasive pneumococcal disease (IPD) is microbiologically defined as detection of Streptococcus pneumoniae in typically sterile clinical samples. Although there are many S. pneumoniae serotypes, only a limited number of them cause most infections. Distribution of pneumococcal serotypes varies by disease, the type of clinical sample studied and geographical region. S. pneumoniae causes a broad spectrum of diseases and represents a significant cause of empyema.¹

The greater or lesser tropism of particular strains for pleural fluid can cause the frequency with which different serotypes are detected to vary in cases of empyema. Serotypes isolated in pleural fluid may be different depending on vaccination policies. The 7-valent pneumococcal conjugate vaccine (PCV7) to protect against serotypes 4, 6B, 9V, 14, 18C, 19F and 23F was placed on the Spanish market in 2001. In 2006, the Autonomous Community of Madrid added this vaccine to its childhood vaccination schedule, and in 2010, it replaced it with the PCV13 vaccine, which added serotypes 1, 3, 5, 6A, 7F and 19A to the PCV7 vaccine. In 2012, the PCV13 vaccine was removed from that vaccination schedule and continued to be recommended on an individual basis. In 2015, the Autonomous Community of Madrid re-added PCV13 to its childhood vaccination schedule.²

IPD is a reportable disease in the Autonomous Community of Madrid, and the Laboratorio Regional de Salud Pública [Regional Laboratory of Public Health] acts as a reference centre for serotyping and monitoring antibiotic susceptibility. The objective of this study is to report changes in the distribution of serotypes in isolates from pleural fluid and their tropism for this type of sample in patients of all ages in the Autonomous Community of Madrid between 2007 and 2018.