Iatrogenic hemolytic anemia and endocarditis in New Zealand White rabbits secondary to Achromobacter xylosoxidans infection

During a 3-mo period, 9 of the 15 New Zealand White rabbits used in a heart failure study developed a hemolytic anemia. The heart failure model involved the creation of an aortic insufficiency (AI) followed 2 to 6 wk later by the creation of an aortic stenosis (AS). None of the 9 animals that developed hemolytic anemia responded to medical management, and 6 of the 9 were euthanized for humane concerns. Necropsies and blood cultures were performed on all anemic animals; 7 of these cultures yielded growth of Achromobacter xylosoxidans. In addition, cultures from the heart valves of 2 rabbits yielded growth of Achromobacter xylosoxidans. We presume that the endocarditis caused by Achromobacter xylosoxidans led to the mechanical damage of red blood cells (RBCs) and subsequent intravascular hemolysis or splenic destruction of damaged RBCs, resulting in a severe, regenerative hemolytic anemia. Achromobacter xylosoxidans is an aerobic, catalase-positive, oxidase-positive, gram-negative bacillus. This organism is an environmentally resistant and opportunistic bacterium that typically inhabits aqueous environments. Microbial samples from the investigator's laboratory and equipment were collected to identify the source of the bacteria. A pressure transducer and bag of intravenous fluid were identified as sources of contamination.