Bacterial Coinfection and Antimicrobial Resistance in Patients with Paranasal Sinus Fungus Balls

Abstract

Objectives The aim of this study was to investigate the incidence of bacterial coinfection and antimicrobial resistance in cases of fungus balls of the paranasal sinuses. Methods Between December 1991 and August 2008, 229 patients underwent endoscopic sinus surgery or the Caldwell-Luc procedure for paranasal sinus fungus ball treatment. From 123 of these patients, a total of 124 specimens were obtained for aerobic and anaerobic culture. Antimicrobial susceptibility tests were performed. Results Ninety-one cultures (73.4%) were positive for bacteria, and 33 showed no bacterial growth. A total of 134 bacterial organisms were isolated: 65 gram-positive, 55 gram-negative, and 14 anaerobic. The most frequently isolated organisms were coagulase-negative Staphylococcus (14.9%), Staphylococcus aureus (12.7%), Enterobacter aerogenes (12.7%), viridans-group streptococci (8.9%), and Pseudomonas aeruginosa (8.2%). Among the gram-positive cocci, 12.2% were resistant to ciprofloxacin, 27.6% to clindamycin, 30% to oxacillin, 35.8% to erythromycin, 35.9% to trimethoprim-sulfamethoxazole, 56.5% to penicillin, 56.8% to gentamicin, and 0% to teicoplanin and vancomycin. Among the gram-negative rods, fewer than 10% were resistant to imipenem, piperacillin-tazobactam, amikacin, gentamicin, ceftazidime, cefepime, and tobramycin, whereas more than 80% showed resistance to ampicillin and cefazolin. When we compared the data from the periods 1991 to 2000 and 2001 to 2008, there were no significant differences in the isolation rates of particular bacterial species and no significant differences in resistance rates except for clindamycin-resistant gram-positive cocci and cefazolin-resistant gram-negative rods. Conclusions Bacterial coinfections were identified in more than two thirds of patients with fungus balls and purulent secretions. This finding suggests that bacterial infection may influence the development and persistence of clinical symptoms in a substantial portion of fungus ball cases.