Pseudoepidemic of Nocardia asteroides associated with a mycobacterial culture system.

Nocardia isolations increased from 0.7 to 11.7/1,000 acid-fast bacillus and mycological cultures (P less than 0.000001). Only three isolations from one patient represented infection. Pseudoepidemic strain identity was confirmed by DNA fingerprinting; the isolate causing infection was distinct. The end of the pseudoepidemic was associated with changing the needle sterilizer and prolonging needle sterilization time on the BACTEC 460 machine. To our knowledge, this is the first reported Nocardia asteroides pseudoepidemic.