Extensively Drug-Resistant Acinetobacter baumannii in Chronic Otomastoiditis: Endoscopic Source Control and Adjunctive Topical Colistin Under Constrained Access to Last-Line Medicines in the European Union—A Romanian Case Report

Background: Carbapenem-resistant Acinetobacter baumannii (CRAB) is a World Health Organization (WHO) critical-priority pathogen. Its role in chronic otologic infection is poorly characterised. In Romania and most Central-Eastern European settings, the practical management of CRAB is constrained by uneven access to last-line agents. Case Presentation: A 16-year-old male adolescent presented with 9 months of left otorrhoea and conductive hearing loss from attic cholesteatoma, refractory to four ambulatory antimicrobial courses. Two superficial aural-discharge swabs yielded Pseudomonas aeruginosa susceptible to ciprofloxacin; sterile intraoperative sampling identified an extensively drug-resistant (XDR) A. baumannii, non-susceptible in five of the six antimicrobial categories tested and retaining activity only against polymyxins. Transcanal endoscopic extended atticotomy with complete cholesteatoma removal provided source control. Topical colistin was then applied to an endaural pack for a defined 14-day course. Otorrhoea resolved, and epithelialisation was complete at 6 weeks, by which time the mean air–bone gap had fallen from 27.5 dB to 2.5 dB and the pure-tone average from 32.5 to 12.5 dB HL, without recurrence at 8-month follow-up. Conclusions: Complete transcanal endoscopic excision of the cholesteatoma was the decisive intervention, with topical colistin given as a short adjunctive course on the operated surface; otorrhoea resolved, the reconstruction epithelialised, and the air–bone gap closed. Local availability of last-line agents shaped the options that were considered but did not determine the outcome of this localised, surgically controlled infection.