Gram Negative Sinusitis: An Emerging Clinical Entity?

Abstract

Traditionally sinusitis has been classified as acute or chronic based on the duration of patient symptoms, and treatment has been based on empiric principles, as the bacteriologic spectrum is felt to be understood, and culturing of nasal secretions has been frowned upon in the past. In this investigation, endoscopically guided cultures were obtained and analyzed from patients, with chronic sinusitis referred to a rhinologic surgeon for evaluation. Often sinusitis was “recalcitrant” to Standard medical and/or surgical therapy. Ninety-eight cultures were obtained from 47 patients with chronic sinusitis who had pathologic sinus secretions noted during the study period. Gram negative enteric bacteria were noted in 47/134 (34.1%) total isolates, a particularly high frequency. Organisms isolated included Pseudomonas aeruginosa, Klebsiella pneumonia, Proteus mirabilis, and Enterobacter aerogenes. The results are significant as gram negative bacteria have been previously reported only infrequently as a cause of sinusitis. Data from this study suggest that endoscopically guided cultures may be helpful in directing medical therapy, especially in longstanding cases of chronic sinusitis that has been “recalcitrant” to traditional medical and surgical therapy. In these patients a shift in the bacterial spectrum to include gram negative organisms, not typically associated with sinusitis, may occur. Empiric selection of standard antimicrobial therapy for chronic sinusitis may not address these bacteria. Classifying sinus disease solely on symptom duration is an oversimplification, and the bacterial spectrum of sinusitis may not be as limited as previous studies suggest. Possible pathophysiologic mechanisms for the shift in the bacterial spectrum and poor response to treatment are discussed.