Usefulness of Creactive protein and procalcitonin determination for the differential diagnosis and guidance of the clinical management in pneumococcal and Legionella pneumonia

Abstract number: P2077

Bellmann-Weiler R., Ausserwinkler M., Schroecksnadel K., Lass-Floerl C., Weiss G.

Objectives: Community acquired pneumonia is a frequent and potentially life threatening infection, Patients' outcome greatly depends on the timely initiation of adequate empirical therapy which is challenging in patients suffering from pneumonia caused either by Streptococcus pneumoniae or Legionella pneumophila since these pathogens have different antibiotic susceptibility patterns. We thus investigated the potential of widely used tests for serum markers of inflammation to differentiate between those pathogens and to guide the clinical management of these infections.

Methods: We retrospectively analysed the records of 60 patients with severe S. pneumoniae (37) or L. pneumophila (23) pneumonia. Diagnosis was confirmed by urinary antigen tests, blood culture and/or serology. The results of C-reactive protein (CRP), procalcitonin (PCT), blood counts, liver and kidney function tests were available on day 1 and day 5 of admission.

Results: While we found no significant differences between patients suffering from S. pneumoniae and L. pneumophila infection at admission in terms of CRP levels, leucocyte counts, haemoglobin concentration or creatinine levels, PCT (p < 0.03), serum sodium (p < 0.02) and chloride levels (p = 0.005) were signficantly lower, and ferritin levels significantly higher (p < 0.01) in pneumonia patients suffering from L. pneumophila than from S. pneumoniae infection. Moreover, patients with L. pneumophila pneumonia more frequently suffered from an underlying chronic obstructive pulmonary disease (p < 0.02), and were more frequently admitted to the intensive care unit (p < 0.05). In both groups, increased PCT levels on days 1 and 5 and high CRP concentrations on day 5 predicted a poor clinical outcome concerning the need of mechanical ventilation or death.

Conclusions: PCT may harbour diagnostic benefits in the early differential diagnosis between S. pneumoniae and L. pneumophila pneumonia. In addition, high PCT levels at admission and follow up are associated with an increased risk for an adverse clinical course and may prompt physicians to consider early intensive care admission.

Session Details

Date: 16/05/2009
Time: 00:00-00:00
Session name: 19th European Congress of Clinical Microbiology and Infectious Diseases
Location: Helsinki, Finland, 16 - 19 May 2009
Presentation type:
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