Bacterial contamination of autologous bone marrow during processing.

As part of an audit of the processing of autologous bone marrow, we found that marrow was often contaminated with organisms potentially pathogenic to neutropenic recipients. One of 14 marrows studied was found to be contaminated before the processing stage and five others became contaminated during processing. The organisms isolated at these stages were Propionibacterium sp., coagulase-negative staphylococci, Staphylococcus aureus and coryneforms, suggesting that the skin was the likely source of contamination. Five out of the 11 marrows returned to patients were found to be contaminated after thawing. Two of these were marrows previously shown to be contaminated with coagulase-negative staphylococci before freezing, and from these coagulase-negative staphylococci were isolated again, in one case the strains were indistinguishable. New organisms isolated after thawing included Bacillus sp. and Corynebacterium sporogenes suggesting contamination from the environment. No infections attributable to these organisms were demonstrated in any of the patients studied.