Serratia marcescens Maxillary Sinusitis and Ethmoiditis in an HIV-Positive Patient Caused by Dental Implant Migrating into the Maxillary Sinus

Iatrogenic maxillary sinusitis accounts for a significant proportion of unilateral sinus infections. This report describes a 36-year-old HIV-positive patient with Serratia marcescens chronic left maxillary sinusitis and ethmoiditis caused by migration of a dental implant into the maxillary sinus. The implant was successfully removed endoscopically via functional endoscopic sinus surgery. Histopathological examination revealed polypoid mucosa with chronic inflammation, while microbiological culture grew Serratia marcescens, an uncommon and opportunistic pathogen. Targeted antibiotic therapy with trimethoprim/sulfamethoxazole was administered for 20 days. Six-month follow-up revealed complete remission without recurrence of sinusitis.