Serotype 5 pneumococci causing invasive pneumococcal disease outbreaks in Barcelona, Spain (1997 to 2011)

Outcomes of Critically Ill Patients Who Have Serotype 5 Invasive Pneumococcal Disease

PURPOSE

To determine whether invasive pneumococcal disease (IPD) due to serotype 5, which occurred as a local outbreak in 2006 to 2007, is associated with intensive care unit (ICU) admission, hospital mortality, or organ supports in those who are critically ill.

MATERIALS AND METHODS

Retrospective review of patients who presented with IPD to 2 tertiary hospitals in Vancouver, Canada, from July 2004 to June 2007. We compared patient characteristics, interventions, and outcomes between patients who had serotype 5 and other serotypes using bivariate and multivariate analyses.

RESULTS

A total of 149 patients had serotype 5 and 106 had nonserotype 5. Patients with serotype 5 were younger, had lower prevalence of comorbid diseases, and had higher rates of substance use than patients with nonserotype 5. There were no differences in chest tube placement for complications of pneumonia or in ICU admission. Frequency of necrotizing pneumonia and hospital mortality were lower in the serotype 5 group. For the 71 patients with IPD who were admitted to ICU, there was no difference in severity of illness, ICU length of stay, or ICU mortality between the groups. There was also no difference in organ supports except that the serotype 5 group was more likely to receive vasopressors.

CONCLUSION

Serotype 5 in patients who have IPD is associated with no difference in ICU admission but with increased use of vasopressors and lower hospital mortality.

Low C-reactive protein values at admission predict mortality in patients with severe community-acquired pneumonia caused by Streptococcus pneumoniae that require intensive care management

Purpose

To identify risk factors associated with mortality in patients with severe community-acquired pneumonia (CAP) caused by S. pneumoniae who require intensive care unit (ICU) management, and to assess the prognostic values of these risk factors at the time of admission.

Methods

Retrospective analysis of all consecutive patients with CAP caused by S. pneumoniae who were admitted to the 32-bed medico-surgical ICU of a community and referral university hospital between 2002 and 2011. Univariate and multivariate analyses were performed on variables available at admission.

Results

Among the 77 adult patients with severe CAP caused by S. pneumoniae who required ICU management, 12 patients died (observed mortality rate 15.6 %). Univariate analysis indicated that septic shock and low C-reactive protein (CRP) values at admission were associated with an increased risk of death. In a multivariate model, after adjustment for age and gender, septic shock [odds ratio (OR), confidence interval 95 %; 4.96, 1.11–22.25; p = 0.036], and CRP (OR 0.99, 0.98–0.99 p = 0.034) remained significantly associated with death. Finally, we assessed the discriminative ability of CRP to predict mortality by computing its receiver operating characteristic curve. The CRP value cut-off for the best sensitivity and specificity was 169.5 mg/L to predict hospital mortality with an area under the curve of 0.72 (0.55–0.89).

Conclusions

The mortality of patients with S. pneumoniae CAP requiring ICU management was much lower than predicted by severity scores. The presence of septic shock and a CRP value at admission <169.5 mg/L predicted a fatal outcome.

Detection and serotyping of pneumococci in community acquired pneumonia patients without culture using blood and urine samples

Background

Treatment of community acquired pneumonia (CAP) patients with antibiotics before laboratory-confirmed diagnosis leads to loss of knowledge on the causative bacterial pathogen. Therefore, an increasing number of pneumococcal infections is identified using non-culture based techniques. However, methods for serotyping directly on the clinical specimen remain scarce. Here we present three approaches for detection and serotyping of pneumococci using samples from patients with CAP.

Methods

The first approach is quantitative PCR (qPCR) analysis on blood samples (n = 211) followed by capsular sequence typing (CST) to identify the serotype. The second approach, a urinary antigen assay (n = 223), designated as inhibition multiplex immunoassay (IMIA), is based on Luminex technology targeting 14 serotypes. The third approach is a multiplex immunoassay (MIA) (n = 171) also based on Luminex technology which detects serologic antibody responses against 14 serotypes. The three alternative assays were performed on samples obtained from 309 adult hospitalized CAP patients in 2007–2010 and the results were compared with those obtained from conventional laboratory methods to detect pneumococcal CAP, i.e. blood cultures, sputum cultures and BinaxNOW® urinary antigen tests.

Results

Using qPCR, MIA and IMIA, we were able to detect the pneumococcus in samples of 56% more patients compared to conventional methods. Furthermore, we were able to assign a serotype to the infecting pneumococcus from samples of 25% of all CAP patients, using any of the three serotyping methods (CST, IMIA and MIA).

Conclusion

This study indicates the usefulness of additional molecular methods to conventional laboratory methods for the detection of pneumococcal pneumonia. Direct detection and subsequent serotyping on clinical samples will improve the accuracy of pneumococcal surveillance to monitor vaccine effectiveness.

Towards New Broader Spectrum Pneumococcal Vaccines: The Future of Pneumococcal Disease Prevention

Seven-valent pneumococcal conjugate vaccine (PCV7) introduction and routine pediatric use has substantially reduced the burden of Streptococcus pneumoniae disease worldwide. However, a significant amount of disease burden, due to serotypes not contained in PCV7, still exists globally. A newly recognized serotype, 6C, was until recently, identified and reported as serotype 6A. This review summarizes the serotype epidemiology of pneumococcal disease pre- and post-introduction of PCV7, available post-marketing surveillance data following the introduction of higher valency pneumococcal vaccines (PCV10, PCV13) and future prospects for the development of new pneumococcal vaccines.