Patterns of bacterial infection in calves implanted with artificial hearts

Device-related infection is one of the most serious potential consequences of total artificial heart (TAH) implantation. This complication must be addressed before the full potential benefit of these devices, especially fully implantable devices, can be realized. A review of research reports and clinical data was conducted to ascertain if similarities existed between the patterns of infection reported in human TAH recipients and those seen in the experimental animal models. Infection was reported in approximately 57% of the human TAH recipients and approximately 47% of the implanted animals. Implant periods ranged from 1-620 days for the humans, and 32-287 days for the animals. The spectrum of organisms isolated from both groups were similar, with a high proportion of infections caused by Pseudomonas aeruginosa and Staphylococcus epidermidis. In addition, numerous isolates of Enterobacter and Enterococci were obtained from the animals. Positive blood cultures have often been observed in animals within 2-4 weeks following implantation of the devices. The similarities noted in this review suggest that the calf may be an appropriate animal model in which to study the pathogenesis of TAH-related infection.