European surveillance of invasive pneumococcal disease. Epidemiology, serotype distribution and antimicrobial resistance patterns

Abstract

Background Streptococcus pneumoniae is responsible for a considerable burden, in terms of both morbidity and mortality. It causes severe diseases such as invasive pneumococcal disease and pneumonia, and is also the causative agent of upper tract respiratory infections that mainly affect children. The introduction of pneumococcal conjugate vaccines in Europe was expected to have an impact on the epidemiology of invasive pneumococcal disease. This made it necessary to study and assess changes in the epidemiology of the disease and its trends, particularly the potential serotype replacement, emergence of new virulent strains, and monitoring of antimicrobial resistance among spreading clones. Material and Methods The study was conceived as an observational study based on the European population and on data from the national surveillance for invasive pneumococcal disease (IPD) in EU/EEA countries in 2010. Data were uploaded into the European Surveillance System (TESSy) hosted by the European Centre for Disease Prevention and Control (ECDC). Twenty-six European countries participated in the surveillance for IPD. A case of IPD was defined as the isolation of Streptococcus pneumoniae or detection of Streptococcus pneumoniae nucleic acid or antigen from a normally sterile site of a patient. The notification rate was defined as the number of laboratory confirmed cases of IPD per 100 000 inhabitants. Population data for denominators were retrieved from the European Statistics (EUROSTAT) website. Data comparisons were performed using the Pearson χ2 and Fisher exact tests. In addition, we conducted a study of risk factors for death of IPD among the variables collected. The study sample was the subsample of cases for which information was available about both serotype and outcome (264 fatal cases). A generalised linear model with robust SEs accounting for the country effect was fitted. Age was an effect modifier of the association between serotype and risk for death, and thus the analysis was stratified by age group. A regression analysis was also conducted. Results In 2010, 21 565 cases of IPD were reported by 26 EU/EEA countries. The Nordic countries (Denmark, Norway, Finland and Sweden) and Belgium had the highest notification rates. The highest notification rates were reported among children below 1 year (18. 5 per 100 000) followed by adults aged 65 years or older (15. 6 per 100 000). In children under 5 years of age, meningitis was the clinical presentation that accounted for the greatest number of deaths while bacteraemia and pneumonia/bacteraemia were the major causes in the age group ≥65 years. The most common serotypes were 19A, 1, 7F, 3, 14, 22F, 8, 4, 12F and 19F. Overall, PCV7 serotype coverage among children 5 years in Europe, was 19. 2%; for the same age group, the serotype coverage for PCV10 was 46. 1% and for PCV13 was 73. 1%. The overall percentage of non-susceptibility was 17. 6% for erythromycin, 8. 9% for penicillin and 2. 7% for cefotaxime. In the main, resistance to erythromycin was predominant in Europe with sixteen countries reporting a proportion above 10%. Countries in Southern and Eastern Europe reported the highest proportion of non-susceptibility of S. pneumoniae to penicillin and/or erythromycin. Simultaneous resistance to penicillin, erythromycin and cefotaxime (multidrug-resistance) was observed for serotypes 19A, 14, 19F, and 23F. Older age, meningitis, non-PCV serotypes among children 5 years of age and PCV7 serotypes among persons 5-64 years of age, and penicillin non-susceptibility were risk factors for death from IPD in Europe. Conclusions The study revealed a need for continued and improved surveillance of IPD throughout Europe, including serotype distribution and antimicrobial resistance. New immunisation strategies are needed to tackle the considerable IPD burden and associated death in children and adults and in designing new extended valence vaccines or protein-based pneumococcal vaccines that may confer serotype-independent immunity. Additionally, policies for the prudent use of antibiotics are warranted.

Date of Award	1 Feb 2016
Original language	English
Awarding Institution	Vall d'Hebron University Hospital (HUVH)
Supervisor	Rosa Maria Bartolomé Comas (Director), Josep Maria Jansa Lopez Del Vallado (Director) & Ignasi Bolibar Ribas (Tutor)