Late Mycobacterium chelonei bioprosthetic valve endocarditis: activation of implanted contaminant?

Mycobacterium chelonei contamination of the Hancock porcine heart valve prosthesis occurred in a few lots manufactured between October, 1975, and August, 1976. The unimplanted valves were recalled, but a number of valves in their cohort had already been implanted. This report describes a patient with Mycobacterium chelonei endocarditis of a Hancock bioprosthetic heart valve belonging to this cohort that occurred three years after implantation. We are aware of four similar instances of mycobacterial endocarditis and believe that these latent infections originated either from surgical inoculation or from implantation of a contaminated valve prosthesis. Other Hancock valves manufactured between October, 1975, and August, 1976, may harbor latent M. chelonei. We believe early valve replacement with aggressive combination antibacterial and antituberculosis therapy is essential for control of atypical mycobacterial valve endocarditis.