Piperacillin-resistant Escherichia coli bacteraemia: relation to empiric therapy and clinical outcome.

Escherichia coli is a leading cause of bacteraemia. The aim of this study was to evaluate all E. coli positive blood cultures collected during a 4-y period in a haematological department using piperacillin plus netilmicin for empiric treatment of febrile episodes. We measured the incidence of piperacillin-resistant E. coli bacteraemia among haematological and non-haematological patients, described the importance of previous antibiotic treatment for resistance development in E. coli and evaluated the impact of piperacillin resistance on the clinical outcome of E. coli bacteraemia. 114 episodes of E. coli bacteraemia in 104 patients were recorded and 98 episodes in 88 patients (42 males and 46 females) with a median age of 64 y (range 19-85 y) were evaluated. In 81.6% of the episodes the patients had a haematological disorder, dominated by acute leukaemia (41.3%), chronic leukaemia (16.3%) and lymphoma (10%). The proportion of piperacillin-resistant E. coli was higher among haematological patients than non-haematological patients (25% vs 0%, p=0.02) and resistance was associated with piperacillin therapy during the previous month (p=0.05). No difference in clinical outcome was found between haematological patients infected with piperacillin-susceptible or -resistant E. coli (intensive care 12% vs 15%; mortality 22% vs 25%).