Microbiological Profiles and Patterns of Resistance in Patients With Sinus Infections After Endoscopic Sinus Surgery.

Objective: Identify common pathogens and antibiotic resistances in chronic rhinosinusitis patients post-endoscopic sinus surgery presenting with an active sinus infection.

Study design: Retrospective chart review.

Setting: Single-institution rhinology private practice in Southeast Florida.

Methods: Recorded postoperative endoscopically-guided sinus cultures from symptomatic patients with purulent drainage on endoscopy from August 2020 to December 2023. When available, pre- or intraoperatively cultured organisms were collected.

Results: Of 125 patients, 50.4% were female with a mean age of 51.0. In 34.4% of patients that underwent revision surgery, 76% had nasal polyps and 26.4% had asthma. Of 301 cultures, 264 (87.7%) were positive, 53 (17.6%) were polymicrobial, and 37 (12.3%) were negative. Of 351 total isolates, 165 (47%) were Gram-negative, 125 (35.6%) Gram-positive, 14 (4%) fungi, and 10 (2.8%) anaerobic. 46.9% of postoperative organisms were not cultured preoperatively. Gram-negative bacteria included Enterobacteriaceae (17.7%), Pseudomonas spp. (10.5%), Serratia spp. (5.1%). Gram-positive bacteria included Methicillin-sensitive Staphylococcus aureus (MSSA, 17.1%) and Methicillin-resistant S. aureus (MRSA, 8%). Antibiotic resistances included MSSA to penicillins (52.8%) and clindamycin (32.8%), and MRSA resistance to quinolones (53.6%) and clindamycin (35.7%). Enterobacteriaceae were 42% resistant to amoxicillin-clavulanate and 37.1% to penicillins, while Pseudomonas aeruginosa was 17.7% resistant to quinolones.

Conclusion: A cohort of chronic rhinosinusitis patients post-sinus surgery grew a large proportion of Gram-negative organisms and significant Staphylococcal penicillin and Gram-negative amoxicillin-clavulanate resistance. Our findings indicate the benefit of culturing patients with this patient presentation. If cultures cannot be obtained, we suggest broad-spectrum antibiotics that consider wide Gram-negative coverage and local antibiotic resistance patterns.