Epidemiology and clinical outcomes of patients with multiresistant Pseudomonas aeruginosa

We conducted a case-series study of multiresistant Pseudomonas aeruginosa i n patients who did not have cystic fibrosis. Patient characteristics, antib iotic exposures, time course of emergence of resistance, and clinical outco mes were examined. Twenty-two patients were identified from whom P. aerugin osa resistant to ciprofloxacin, imipenem, ceftazidime, and piperacillin was isolated. Nineteen (86%) had clinical infection. Patients received prolong ed courses of antipseudomonal antibiotics before isolation of multiresistan t P. aeruginosa. Nine of 11 patients with soft-tissue infection exhibited r esolution of clinical infection but usually required surgical removal of in fected tissue with or without revascularization. Overall, three patients di ed. In two instances in which multiple isolates with different susceptibili ty profiles from the same patient were available, pulsed-field gel electrop horesis profiles of serial isolates were indistinguishable or closely relat ed. This study illustrates that multiresistant P. aeruginosa emerges in a s tepwise manner after exposure to antipseudomonal antibiotics and results in adverse outcomes.