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Severe Mycoplasma pneumoniae respiratory tract infections in children, suspected on clinical ground, are confirmed by laboratory tests

Abstract number: P1801

Marangoni A., Delucca F., Bergamaschi R., Zama D., Specchia F., Accardo S., Moroni A., Cevenini R.

Objectives: About 15%-20% of cases of community-acquired pneumonias are estimated to be due to Mycoplasma pneumoniae, whereas 1% to 5% of M. pneumoniae pneumonias may require hospitalization for respiratory distress. In these cases, a specific diagnosis is essential for the choose of the antimicrobial treatment since b-lactam antibiotics, often delivered to young outpatients with pneumonias, are ineffective against M. pneumoniae.

In this study, children hospitalized for suspected pneumonia not-responder to the treatment with b-lactam antibiotics, were studied in order to etiologically diagnose M. pneumoniae infection, both by polymerase chain reaction (PCR) and serology.

Methods: Study group. From January 2009 to October 2009 two paired samples (a nasopharingeal aspirate specimen and a serum specimen) were taken on hospital admission from children hospitalized for suspected pneumonia diagnosed on clinical ground and confirmed by radiology. Specimens were obtained from a total of 61 children (aged between 1–14, mean age 5.5) hospitalized at S. Orsola Hospital, Bologna, Italy, during the study period.

Molecular diagnosis of M. pneumoniae infection. Automated DNA extraction was performed by using Nuclisens® easyMag system, bioMérieux. Real Time PCR was performed by using MYCOPLASMA pn. Q - PCR Alert AmpliMIX, Nanogen Advanced Diagnostics. System standardization was carried out on Applied Biosystems ABI PRISMTM 7300 instrument. M. pneumoniae serology. We used Mycoplasma pneumoniae IgG e IgM Novagnost™, Siemens Healthcare Diagnostics, for the serological diagnosis of M. pneumoniae.

Results:M. pneumoniae was detected by PCR in aspirate specimens of 11 of 61 (18%) patients with pneumonia. All the PCR-positive patients but one had also IgM positive results on serum samples.

In 10/61 aspirate specimens the first result of the amplification reaction was undetermined for the DNA of the human b-globin gene.

Conclusion: The concordance of M. pneumoniae PCR and IgM serology in 10 out of 11 (90.9%) young patients hospitalized with pneumonia, confirmed that the timing of pathological samples collection for laboratory investigations in M. pneumoniae pneumonias is crucial for optimizing the results. In addition, the rapid acquisition of the laboratory results allowed the clinicians to modify the antimicrobial therapy without delay, by replacing b-lactam antibiotics with macrolides.

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
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