Gram-negative bacteraemia (GNB) after 428 unrelated donor bone marrow transplants (UD-BMT): risk factors, prophylaxis, therapy and outcome

Gram-negative infection is an important cause of morbidity and mortality after unrelated donor-bone marrow transplantation (UD-BMT). We performed a retrospective case-control study to examine the risk factors, prophylaxis, therapy and outcome of Gram-negative bacteraemia (GNB) in 428 patients undergoing UD-BMT. The incidence of GNB was 3.6% in children and 19% in adults. Of the adults, 11% developed GNB 460 days post UD-BMT. Predisposing risk factors for GNB included 'high-risk' disease status, chronic graft-versus-host disease and use of systemic steroids. Fever, a raised C-reactive protein (CRP) and hypotension were common findings at presentation. Patients were routinely given prophylactic ciprofloxacin: resistance to this antibiotic was seen in 33% of isolates. We identified an age-matched control group undergoing UD-BMT over the same time period as the study group. Gram-positive bacteraemia was significantly more common in cases than controls. Mortality from GNB was 17% in children and 24% in adults. We conclude that GNB is a common complication of UD-BMT with a high associated mortality. Patients should be educated further to present rapidly with symptoms suggestive of infection.