Resistance to antibiotics in Pseudomonas aeruginosa in Colombian hospitalsPseudomonas aeruginosa infections cause high morbidity and mortality.We performed a descriptive analysis of the rates of antibiotic resistance in isolates of P. aeruginosa in 33 hospitals enrolled in a surveillance network in Colombia.The study was conducted between January 2005 and December 2009 .9905isolates of P. aeruginosa were identified,(4.9 % of all strains).In intensive care units (ICU) P. aeruginosa showed an overall resistance to aztreonam, cefepime , ceftazidime, imipenem, meropenem , and piperacillin / tazobactam of 31.8% , 23.9% , 24.8%, 22.5%, 20.3% and 22.3%, respectively.Resistance rates increased for piperacillin/tazobactam, cefepime, and imipenem; remained unchanged for meropenem; and decreased for aminoglycosides, quinolones and ceftazidime.Resistance to one, two and three or more families of antibiotics was found in 17%, 12.5%, and 32.1%, respectively.In samples collected from the wards, the resistance rate was lower but usually over 10%.Antibiotic resistance in P. aeruginosa isolates in hospitalized patients and particularly in those admitted to ICUs in Colombia is high.