Culture Negative Endocarditis

An elderly male in his 70s with a history of aortic valve replacement (prosthetic) 3 years prior, presented to his PCP with Fever, Malaise, Weight loss, Anemia, high blood sedimentation rate. Intraoperative transesophageal echocardiography (TEE) was performed which showed no vegetations. Blood cultures were negative. Serology for Chlamydia, Mycoplasma, Legionella were all negative. With no diagnosis, he was placed on 8 wk course of ceftriaxone, gentamycin, and vancomycin antimicrobials. He returned 4 weeks later with increasing shortness of breath. TEE showed a perivalvular leak. His pacemaker showed no vegetation around it. He was thrombocytopenic. Unusual forms of endocarditis suspected. Serology for Bartonella was indeterminate. He was referred to surgery for aortic valve replacement and mitral valve repair. Tissue (aortic valve) came to UWMC molecular microbiology section for 16S gene amplification/sequencing and Bartonella specific PCR. A PCR test for Tropheryma was also requested. Q-fever (Coxiella burnetii) serology was sent to another laboratory.

Sequence of 16S PCR fragment matched C. burnetii 16S gene sequence in the NCBI database. Bartonella specific PCRs were negative (UWMC, molecular microbiology). Subsequently, Q-fever serology results came back and confirmed the 16S gene sequencing results.

It was then revealed that the patient had traveled abroad last summer, but had been sick before that so never mentioned it. He further recalled that he had been abroad a year before that, where he spent time on a farm.

He was treated with doxycycline and placed on coumidin.

Please refer to Available Tests for more information about TSEXAM for bacteria.