The findings, published in the May 23, 2018, issue of the Journal of the American College of Cardiology, suggest that patients with a higher risk of infection after device implantation may be identified by performing a genetic analysis of the implanted device.
"Currently, we do not fully understand why some patients develop infections following device implantation while others do not," said senior author Sriram Machineni, MD, assistant professor of medicine in the Division of Infectious Diseases at UC San Diego School of Medicine. "In this study, we took a novel approach, using whole genome sequencing of staphylococcal isolates, to identify genetic factors that may be responsible."
Staphylococcal infections are a leading cause of bloodstream infections, device infections and death after cardiovascular implantable electronic device (CIED) implantation, such as pacemakers and implantable cardioverter-defibrillators. Staphylococcus aureus is a major cause of these infections; other staphylococcal species, such as Staphylococcus lugdunensis and Staphylococcus schleiferi subsp. coagulans, are also known to cause device-associated infections, although less commonly.
Cardiac implantable electronic devices play an increasingly important role in the management of various cardiovascular conditions. However, device infections remain a serious complication and a major cause of morbidity and mortality.
"While infection rates associated with device implantation are low, they are particularly concerning because treating device infections is complex, can require removal of the device, and is often associated with prolonged hospital stays and increased mortality," said Machineni. "It is important to note that the majority of patients do not develop infections after device implantation, and our findings should be interpreted in this context."
The researchers conducted a retrospective analysis of consecutive patients undergoing CIED implantation at UC San Diego Health between 2011 and 2014, identifying those patients who developed a staphylococcal device infection during the study period. They then used whole genome sequencing to analyze staphylococcal isolates obtained from the infected devices and compared them to isolates collected from patients without device infections.
The investigators found that patients with device infections had a higher prevalence of staphylococcal isolates with specific genes that may contribute to device colonization, biofilm formation and immune evasion, suggesting that these genes may contribute to the development of device-associated infections.
"In addition to identifying patients with a higher risk of device infection, the long-term goal is to develop novel strategies to prevent or treat device-associated infections based on the genetic characteristics of the infecting organisms," said Machineni. "However, more research is needed."
