Original articleClinical and microbiological characteristics of unusual manifestations of invasive pneumococcal diseaseCaracterísticas clínicas y microbiológicas de las manifestaciones inusuales de la enfermedad invasiva neumocócica
Introduction
Invasive pneumococcal disease (IPD) is defined as isolation of Streptococcus pneumoniae in blood or another organic sterile fluid. Despite the reduction in incidence of IPD following the introduction of pneumococcal conjugate 7-valent and 13-valent vaccines (PCV7/PCV13) IPD remains an important health problem with an incidence of 6.6–14.2 cases per 100,000 patients per year1, 2 and with a mortality ranging between 10% and 30%.3, 4
Even though S. pneumoniae can produce infection in any site of the organism,5 more frequent clinical presentations of IPD are bacteremic pneumonia, meningitis and primary bacteraemia. Other clinical presentations, such as arthritis, spontaneous bacterial peritonitis or endocarditis are occasionally seen in clinical practice.6, 7
Host-related factors, such as age or predisposing comorbidities (human immunodeficiency virus infection, chronic liver disease, diabetes mellitus, splenectomy or connective tissue disease) influence clinical presentation and outcome of patients diagnosed with IPD.8, 9
Also, different pneumococcal serotypes are known to cause different pneumococcal clinical syndromes (i.e. serotypes 1 or 7 and empyema)4, 10 and different outcomes.11 On the other hand, following the introduction of 7-valent pneumococcal conjugate vaccine in Europe and US, different authors have observed a change in IPD clinical presentations in the last few years with increase in empyema and severe pneumonia cases and a decrease in incidence of meningitis.12, 13, 14 These changes have been linked to a replacement of serotypes included in conjugate vaccine to others, like 35B or 11A.
The objectives of our study were to analyse clinical forms, microbiological profile, epidemiology and outcome of patients with unusual invasive pneumococcal disease (uIPD) as well as to evaluate the possible correlation between the profile of serotypes and the clinical forms of this type of IPD.
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Materials and methods
The study was carried out in Complejo Hospitalario Universitario de Vigo, a 1300 bed tertiary teaching hospital, serving a population of almost 600,000 inhabitants. All S. pneumoniae isolated from blood or another steril fluid between January 1992 and December 2014, in adult and paediatric patients, were studied. Epidemiological data and comorbidities of IPD patients were collected, as well as characteristics of the infection (clinical form, severity of infection, empirical treatment, hospital
Results
A total 389 patients with IPD were identified, 22 (6%) of them met uIPD criteria. Epidemiological characteristics of IPD and uIPD patients adjusted by age-groups are shown in Table 1. Data from 47 patients were not complete so they were excluded from the analysis.
Patients in 15–65 years-old group and as compared IPD patients with patients with uIPD, these last had a higher proportion of Charlson Index >2 (54.5% vs 24%; p = 0.03); more chronic liver disease (36.3% vs 8.5%, p = 0.002) and lower
Discussion
Following the implementation of conjugate vaccines, the incidence of IPD dramatically decrease globally around the world.18, 19 Nevertheless some authors13, 17, 28 like Burgos et al.14 reported an increase in the overall incidence of invasive pneumococcal pneumonia in adults, associated with serotype replacement, following the introduction of the PCV7 vaccine in Spain. In addition, there was a trend towards greater proportion of case-fatalities in patients aged 51–65 years, while in younger
Funding
None to declare.
Conflict of interest
None of the authors have any disclosure.
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