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Senin, 04 Agustus 2008

Mycrobiology of sinusitis

A.Acute sinusitis
The most commonly identified organisms in children with acute sinusitis are Streptococcus pneumoniae in 30% to 40%, Haemophilus influenzae in 20% to 25%, and Moraxella catarrhalis in 20%. In adults, S. pneumoniae and H. influenzae are the two leading causes of acute sinusitis, whereas Moraxella is unusual. Anaerobic organisms are primarily identified in cases of acute sinusitis originating from dental root infections, but are otherwise uncommon. Hospital-acquired sinusitis is most often seen as a complication of nasogastric tube placement, and is typically caused by gram-negative enteric organisms, such as Pseudomonas and Klebsiella species.

B.Chronic sinusitis

1.Bacteria cultured from children with persistent symptoms are usually the same as those seen in acute disease. In children with more severe and protracted symptoms, anaerobic species (such as Bacteroides) and staphylococci are cultured more frequently. In adults with refractory symptoms, Staphylococcus epidermidis is frequently cultured from intraoperative specimens. The exact role of this species in the pathogenesis of chronic sinusitis is unclear. Although anaerobic organisms were once implicated in adults with chronic sinus disease, more recent evidence casts doubt upon those data.

2.Fungi, such as Aspergillus species, are a common cause of sinus disease in immunocompromised hosts, including diabetics and patients who have defective cell-mediated immunity. Increasingly, fungi have been identified as causes of sinusitis in patients who are otherwise healthy and should, therefore, be considered in cases of refractory sinusitis. Allergic fungal sinusitis is a syndrome that occurs in adults with asthma and has been attributed to Aspergillus, Bipolaris, and Curvularia species. It is characterized by severe, hyperplastic sinusitis and nasal polyposis, and is associated with significant eosinophilia of sinus tissue and blood.