Title : A case of aortic root abscess and repeated prosthetic aortic valve dehiscence in the setting of rare infection with Cellulosimicrobium cellulans and Corynebacterium tuberculostearicum
Abstract:
Cellulosimicrobium cellulans and Corynebacterium tuberculostearicum are commensal skin flora that rarely cause human infection. Due to their ubiquitous nature, blood and tissue cultures identifying these organisms are regularly dismissed as contaminants, delaying appropriate antibiotic treatment. However, over the past two decades, there have been increasing instances of infection from these organisms and are associated with significant mortality.
A 60 year-old female with a history of ventriculoperitoneal shunt and congestive heart failure from severe aortic regurgitation presented with dyspnea on exertion. After appropriate workup, she was admitted to cardiac surgery and underwent aortic valve replacement and coronary artery bypass grafting. During the procedure a non-purulent aortic root abscess was noted and debrided. Blood cultures taken at this time returned negative. She had uncomplicated postoperative course and was discharged on post-operative day 23. Approximately four months after the procedure, the patient presented to an outside hospital with acute shortness of breath. Echocardiogram showed valve dehiscence and she was emergently taken to the operating room where the valve was found to be circumferentially dehisced. The aortic root annulus was repaired and a valve replacement performed for the second time. The patient was discharged on post-operative day 18 to subacute rehab. Four months after the second operation, the patient returned to the primary hospital with left sided chest pain and shortness of breath. Echocardiogram showed severe aortic regurgitation secondary to a recurrent valve dehiscence. The patient was taken to the operating room for an aortic root replacement and again tissue cultures remained negative. Due to repeated valvular dehiscence the patient was started on empiric ceftriaxone and vancomycin and intra-operative tissue cultures were sent out for polymerase chain reaction (PCR) testing. The PCR identified Cellulosimicrobium cellulans and Corynebacterium tuberculostearicum as the infectious agents and the patient was continued on appropriate treatment following sensitivity studies. She was discharged in stable condition on one month of daily vancomycin with planned lifetime Bactrim prophylaxis.
Cellulosimicrobium cellulans and Corynebacterium tuberculostearicum are exceedingly rare drivers of infections in humans. As such, these organisms are routinely discarded as contaminants of blood and tissue cultures. Through this case, we show that these organisms should be taken into consideration in cases of prolonged culture negative infection, especially in patients harboring foreign bodies or in immunocompromised states.
