Abstract
BackgroundAdult invasive pneumococcal disease (IPD) occurs mainly in the elderly and patients with co-morbidities. Little is known about the clinical characteristics, serotypes and genotypes causing IPD in healthy adults.MethodsWe studied 745 culture-proven cases of IPD in adult patients aged 18–64 years (1996–2010). Patients were included in two groups: 1.) adults with co-morbidities, and 2.) healthy adults, who had no prior or coincident diagnosis of a chronic or immunosuppressive underlying disease. Microbiological studies included pneumococcal serotyping and genotyping.ResultsOf 745 IPD episodes, 525 (70%) occurred in patients with co-morbidities and 220 (30%) in healthy adults. The healthy adults with IPD were often smokers (56%) or alcohol abusers (18%). As compared to patients with co-morbidities, the healthy adults had (P<0.05): younger age (43.5+/−13.1 vs. 48.7+/−11.3 years); higher proportions of women (45% vs. 24%), pneumonia with empyema (15% vs. 7%) and infection with non-PCV7 serotypes including serotypes 1 (25% vs. 5%), 7F (13% vs. 4%), and 5 (7% vs. 2%); and lower mortality (5% vs. 20%). Empyema was more frequently caused by serotype 1. No death occurred among 79 patients with serotype 1 IPD. There was an emergence of virulent clonal-types Sweden1-ST306 and Netherlands7F-ST191. The vaccine serotype coverage with the PCV13 was higher in healthy adults than in patients with co-morbidities: 82% and 56%, respectively, P<0.001.ConclusionIn this clinical study, one-third of adults with IPD had no underlying chronic or immunosuppressive diseases (healthy adults). They were often smokers and alcohol abusers, and frequently presents with pneumonia and empyema caused by virulent clones of non-PCV7 serotypes such as the Sweden1-ST306. Thus, implementing tobacco and alcohol abuse-cessation measures and a proper pneumococcal vaccination, such as PCV13 policy, in active smokers and alcohol abusers may diminish the burden of IPD in adults.
Highlights
Streptococcus pneumoniae remains a major cause of morbidity and mortality worldwide
Definitions Culture-proven invasive pneumococcal disease (IPD) was defined according to the clinical findings and the isolation of Streptococcus pneumoniae from a normally sterile body fluid such as blood, pleural fluid, cerebrospinal fluid (CSF), peritoneal fluid or joint fluid
Between 1/1996 and 12/2010, we studied 1414 IPD episodes in adult patients, in whom S.pneumoniae was isolated from one or more sterile site: blood 1320, pleural fluid 128, CSF 107, abdominal fluid 68, and joint fluid 2
Summary
Invasive pneumococcal disease (IPD) occurs mainly in young children and older adults ($65years) as well as in patients with comorbidities (e.g., chronic lung disease, cardiovascular disease, cirrhosis, malignancies, HIV, asplenia) [5,6]. The 7-valent pneumococcal conjugate vaccine (PCV7), which usually produces a better immunologic response and may reduce acquisition of nasopharyngeal carriage, was introduced in the year 2000 for children in the USA [11] and it was followed by a decline in IPD caused by vaccine serotypes in children as well as in adults - through an indirect effect (herd protection) - [11,12]. Adult invasive pneumococcal disease (IPD) occurs mainly in the elderly and patients with co-morbidities. Little is known about the clinical characteristics, serotypes and genotypes causing IPD in healthy adults
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