Culture-negative endocarditis is an infection and inflammation of the lining of one or more heart valves, but no endocarditis-causing germs can be found in a blood culture. This is because certain germs do not grow well in a laboratory setting, or some people have received antibiotics in the past that keep such germs from growing outside of the body.
Endocarditis is usually a result of a bloodstream infection. Bacteria can enter the bloodstream during certain medical procedures, including dental procedures or through intravenous injection using non-sterile needles. Then bacteria can travel to the heart, where they can settle on damaged heart valves.
Reviewed By: Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.