Culture-negative bacterial endocarditis may be attributed to fastidious microorganisms, prior institution of antibiotic treatment, or both. We describe a case of culture-negative endocarditis in which a modified Steiner stain revealed bacterial structures in the resected heart valve material. Prompted by this finding, broad-range polymerase chain reaction (PCR) amplification of small-subunit ribosomal DNA (16S rDNA) was performed, and Cardiobacterium hominis sequences were detected. This case demonstrates the usefulness of both the Steiner stain and broad-range direct molecular amplification as supplemental diagnostic tools in identification of otherwise unexplained infections.
Nikkari S, Gotoff R, Bourbeau PP, Brown RE, Kamal NR, Relman DA. Identification of Cardiobacterium hominis by Broad-Range Bacterial Polymerase Chain Reaction Analysis in a Case of Culture-Negative Endocarditis. Arch Intern Med. 2002;162(4):477-479. doi:10.1001/archinte.162.4.477