Abstract
Postoperative endophthalmitis is a rare but severe complication of phacoemulsification cataract surgery (PCS). Acinetobacter baumannii is an uncommon pathogen, often associated with multidrug resistance and poor outcomes. In this report, a 73-year-old male who developed endophthalmitis following PCS is introduced, who, despite intensive empirical therapy, experienced no clinical improvement. Following a vitreous sample analysis with polymerase chain reaction, A. baumannii infection was diagnosed. The patient was treated with fortified topical colistin, amikacin, and subconjunctival and intravitreal colistin, which responded with the resolution of intraocular inflammation. This case emphasizes the therapeutic challenges of A. baumannii endophthalmitis. It highlights colistin as an effective treatment option in cases resistant to conventional regimens.