Infective endocarditis caused by gram-negative bacteria: a review of the literature, 1945-1977.

N sharp contrast to the relatively high frequency with which gram-positive cocci are involved in the pathogenesis of infective endocarditis, has been the paucity of reports of this disease in which gram-negative bacteria are involved. This difference becomes striking when one considers the high incidence of bacteremia with gram-negative organisms associated with infection or manipulation of the genitourinary and intestinal tracts (areas in which these species are numerous) and is especially notable because these involve primarily older individuals, many of whom have underlying atherosclerotic or valvular disease, but very few of whom develop endocardial infection. The rarity of endocarditis complicating typhoid fever, in which bacteremia is present in all patients, or salmonella gastroenteritis, during which invasion of the blood stream is not uncommon in the young and elderly, emphasizes this point. Although there has been a recent increase in the incidence of endocarditis caused by gram-negative bacteria in individuals addicted to the intravenous use of drugs and in those with cardiac prostheses, this remains a relatively uncommon type of disease. Because a thorough search of the medical literature failed to disclose an extensive and detailed review of the problem of endocarditis caused by gram-negative bacteria, it was decided to collect as many papers as possible describing this type of disease that have been published in English between 1945 and 1977 and to analyze the microbiologic, pathologic, and clinical features of the reported cases. In addition, more recently recorded experiences permitted a review of the effectiveness of various therapeutic, prophylactic, and diagnostic maneuvers. Finally. an attempt has been made to define some characteristics of this kind of endocarditis that might distinguish it from the more common form in which gram-positive cocci are involved.