Recent Advances in the Microbiology of Sinusitis and Their Relation to Persistent Ethmoidal Inflammation

Abstract

The organisms that commonly cause acute sinusitis have been found to produce a number of factors which may be involved in the transition to a state of chronicity. These factors, combined with increasing ostial obstruction caused by tissue inflammation, propagate a hypoxic environment which favors pathogen survival at the expense of host defenses. Bacterial toxins and hypoxia disrupt the mucociliary clearance system. Both aerobic and anaerobic organisms produce proteases, which may act synergistically to cause immune subversion and prevent opsonization. We have studied the role of bacteria in persistent ethmoid mucosal inflammation in 13 patients undergoing endoscopic endonasal surgery for recurrent acute or chronic sinusitis and found that in 46% of samples there was no significant growth of bacteria but in 33% there was a significant growth of anaerobes. There appeared to be little evidence for synergistic activity between aerobes and anaerobes. Mucosal apposition may account for persistent inflammation in those cases without any significant growth. There is no evidence that the ethmoid sinus acts as a reservoir for reinfection, and it appears likely that acute exacerbations in chronic sinusitis are caused by viral infection. Treatment should be aimed at restoring the host's mucosal defenses either medically with topical decongestants or surgically by endoscopic endonasal surgery. Recurrent courses of antibiotic treatment are not indicated.