Mycobacterium chelonae valve endocarditis resulting from contaminated biological prostheses.

Objectives: A rapid-growing mycobacteria biological prosthetic valve (BPV) endocarditis related to prosthetic manufacturing process is described in Brazil.

Methods: From 1999 to 2008, thirty-nine patients underwent BPV replacement due to culture-negative suspected endocarditis. All these cases had histological sections stained by Ziehl-Neelsen method. Clinical and microbiological data were reviewed in all acid-fast bacilli (AFB) positive cases. The 16S-23S internal transcribed sequence (ITS) was amplified using DNA extracted from paraffin-embedded samples, digested with restrictions enzymes and/or sequenced.

Results: Eighteen AFB positive BPV (18/39)(46%) were implanted in 13 patients and were from the same manufacturer. Four of them were implanted in other hospitals. Thirteen BPV were histologically proven endocarditis and five showed a colonization pattern. The examination of six non-implanted "sterile" BPV from this manufacturer resulted in 5 AFB positive. Mycobacterium chelonae was the AFB identified by ITS restriction analysis and sequencing.

Conclusions: Rapid-growing mycobacteria infections must be suspected and Ziehl-Neelsen stain always performed on histology of either early or late BPV endocarditis, particularly when blood cultures are negative.