The multiresistant Acinetobacter species bacteria are frequently involved in urinary or respiratory tract infections, and one of the most effective drugs, colistine, is associated with significant nephrotoxicity and neurotoxicity. Given that very high concentrations of colistine into biological fluids are safe for the human organism, attempts have been made at delivering the drug topically, by aerosol, or, occasionally, intratechally or intraventricularly for meningitis. These topical treatments could eradicate the Pseudomonas sp. from the lung of patients with cystic fibrosis or bronchiectasis and the Acinetobacter baumannii from lung and meninges. However, only one case of colistin topic treatment in urinary tract infection is described. We report a case series of three patients successfully undergone colistin bladder instillations for multi drug resistant Acinetobacter urinary tract infection, and we review the literature about colistin topic treatment.