Amplification of conserved 16S rDNA sequences in the diagnosis of subdural empyema complicating sinusitis
Abstract number: 1134_01_322
Sprecher H., Shalginov R.
To demonstrate the usefulness of broad-range PCR amplification and sequencing of 16S rDNA in the diagnosis of culture-negative subdural empyema (SDE), complicating sinusitis.
DNA was extracted from sinus discharge and SDE samples. Broad-range amplification of bacterial DNA was carried out using primers aimed at the 16S rRNA gene. PCR amplicons were directly sequenced and resulting sequences were analysed using BLAST analysis.
Case1: a 12-year-old male child was admitted to the pediatric ward because of severe headache accompanied by fever (400°C) and vomiting. Bilateral ethmoid and maxillary sinusitis was demonstrated by CAT scan without brain involvement. After 6 days of treatment with intravenous ceftriaxone and metronidazole, he developed hemiplegia, aphasia and disorientation. CAT scan demonstrated SDE. The SDE and sinuses were drained. Subsequent course was uneventful. Case 2: a 15-year-old male, presented with headache, fever and nasal discharge. He had been treated with oral amoxicillin-clavulanic acid for several days before admission. CAT scan demonstrated pansinusitis. He received intravenous ceftriaxone and metronidazole. Three days later the patient developed focal convulsions. CAT scan demonstrated a large SDE. The empyema and sinuses were drained. No pathogens were demonstrated by Gram stain and aerobic and anaerobic cultures obtained from both patients. Broad-range 16S rDNA PCR resulted in positive amplicons in both patients' SDE samples. Direct sequencing of the positive amplicons identified nucleotide sequences specific to S. intermedius in case 1, and to S. Pyogenes in case 2.
Intracranial infections complicating sinusitis are not common, but may be devastating. Microbiological diagnosis is complicated by a wide range of causative pathogens and jeopardized by the fact that many patients are already treated with antibiotics at presentation. Broad range PCR sequencing provides a rapid and accurate methodological solution in cases of partially-treated bacterial infections of unknown etiology, giving clues to the etiologic agents and probably better guide antimicrobial therapy.
|Session name:||XXIst ISTH Congress|
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