Infective Endocarditis Due to Nontoxigenic Corynebacterium diphtheriae: Report of Seven Cases and Review

Abstract

We report seven cases of endocarditis due to nontoxigenic Corynebacterium diphtheriae that occurred between October 1990 and September 1991. The patients all lived in the state of New South Wales, Australia. Three patients had preexisting cardiac abnormalities, and one patient used intravenous drugs regularly. The other three patients had no known risk factors for endocarditis. Notable clinical features were the aggressive nature of the infection, the occurrence of septic arthritis in four patients, and major vascular complications in four patients, one of whom died. One patient required urgent mitral valve replacement. All of the isolates were identified as non-toxigenic C. diphtheriae var gravis. Sporadic cases of endocarditis due to C. diphtheriae have rarely been reported; septic arthritis complicating endocarditis due to this organism has not previously been described. This report highlights the importance of identifying Corynebacterium isolates from normally sterile sites at the species level.

Emergence of an Invasive Clone of Nontoxigenic Corynebacterium diphtheriae in the Urban Poor Population of Vancouver, Canada

“…Even in the absence of toxin production, C. diphtheriae appears to have an impressive propensity to cause invasive bloodstream infections. Systemic complications of C. diphtheriae bacteremia are not unusual and include endocarditis, joint infections, and peripheral embolic disease (28). The pathogenesis for nontoxigenic C. diphtheriae infections remains unknown, although the various manifestations of severe disease suggest that the organism has a predilection for endocardial and synovial tissues.…”

Endocarditis Due to Rare and Fastidious Bacteria

“…Few laboratories perform tests for identification of the gram-positive Corynebacterium diphtheriae. A total of 67 cases of nontoxigenic C. diphtheriae endocarditis have been reported in the literature, and half were reported before 1950 (197,278; O. Lortholary, A. Buu-Hoi, L. Gutmann, and J. Acar, Letter, Clin. Infect.…”

“…17:1072-1074, 1993). Sporadic cases may be observed, but most occur as small outbreaks or in clusters (278). Since the source of the organism is likely to be the upper respiratory tract or skin, a history of pharyngitis or intravenous drug use is frequent.…”

Potential pathogenic role of aggregative- adhering Corynebacterium diphtheriae of different clonal groups in endocarditis

“…Few reports have dealt with the microbiological aspects of community-acquired endocarditis caused Corynebacterium diphtheriae and endocarditis www.bjournal.com.br by C. diphtheriae (4)(5)(6). Entry of C. diphtheriae by invasive processes was described as being caused by percutaneous trauma, skin (7,8) and throat colonization (9). Unlike classical diphtheria, invasive disease caused by C. diphtheriae affects both vaccinated and non-vaccinated persons, and is mostly induced by nontoxigenic isolates (10).…”