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Procalcitonin in the diagnosis of acute bacterial otitis media

Abstract number: P2200

Arguedas A., Dagan R., Leibovitz E., Pavlova-Wolf A., Wang E., Song J., Echols R.

Objective: PCT has been used for differentiating clinical syndromes that may be associated with bacterial infection from those that are not. The accuracy of PCT as a diagnostic test to differentiate between bacterial and non-bacterial AOM was studied in an investigator-blinded dose ranging study of faropenem medoxomil in AOM.

Methods: 328 subjects aged 6 months to <7 years were enrolled in a double tympanocentesis study of AOM. 277 subjects were analysed after excluding those who had received antibiotics in the preceding 7 days and those missing a baseline PCT assay. Subjects were evaluated using the Dagan severity of symptoms score consisting of scores of 5 signs and symptoms with a possible maximum score of 15. A PCT value of 0.5 ng/ml was used as a cutpoint indicating bacterial infection.

Results: 164 subjects (59%) had single or mixed bacterial pathogens cultured from middle ear fluid. PCT levels in the different groups (Table).

There was no difference in mean Dagan scores or PCT levels between bacterial and non-bacterial AOM. The mean PCT concentration was higher in S. pneumoniae and mixed infections vs. non-bacterial AOM, but this did not reach statistical significance. At cutpoints of 0.05 or 0.5, the likelihood ratio of a positive test indicating a S. pneumoniae infection (vs. non-bacterial infection) is 1.2 and 3.5, respectively. The sensitivity and specificity are 41% and 66% for 0.05 and 7% and 98% for 0.5 cutpoints. Mean PCT concentration was more than halved at TOC regardless of bacteriologic or clinical outcome.

Conclusion: PCT was unable to differentiate bacterial from non-bacterial AOM, even when the most inflammatory infection due to S. pneumoniae is the cause. This may be due to the lesser degree of inflammation with AOM compared with sepsis or pneumonia. PCT level cannot be used to decide upon initiation of an antibiotic to treat AOM.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Barcelona, Spain
Presentation type:
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