A nightmare for haematology clinics: extensively drug-resistant (XDR) Acinetobacter baumannnii

The purpose of our study was to share experience on demographic characteristics and clinical outcome of the patients infected with extensively drug-resistant Acinetobacter baumannii (XDRAB) in haematology clinics, focusing on the period with a sudden increase in the number of XDRAB cases. A regular patient-based infection control programme was set up in haematology clinics and haematopoietic stem cell transplant centre starting from 2008. An infection control nurse visited all patients daily. A form including demographic data and laboratory results were recorded for all patients. The source of infections was identified according to the criteria proposed by the Centers for Disease Control and Prevention. While haematology ward-acquired XRDAB was rare before 2012, between January 2012 and July 2013, 29 A. baumannii infection episodes were detected in 28 patients. All but one isolate were MDR and 72.4% (21 out of 29) were XDR. Blood cultures revealed A. baumannii in 26 out of 29 episodes. While the haematological malignancy was relapsing or not under remission in 15 patients, four patients were under remission, and 10 patients were newly diagnosed. The mortality rate was 81.2%. All patients with a poor outcome died in the first week after the index blood culture was performed. In 16 out of 29 episodes, the patients died before the culture results became available. Colistin was initiated for the treatment in 11 out of 29 episodes. Three patients received colistin combined with sulbactam or sulbactam containing beta-lactams; the remaining eight patients who received colistin monotherapy were already under carbapenems. In conclusion, XDRAB infections can easily become nightmares for haematology clinics without any reliable treatment option.