Pseudo-outbreak of Mycobacterium chimaera through aerators of hand-washing machines at a hematopoietic stem cell transplantation center.

We identified a waterborne pseudo-outbreak of Mycobacterium chimaera in our stem cell transplantation center, which likely resulted from biofilm on the aerators of the handwashing machines in each patient's room. Regular replacement of faucet parts can prevent biofilm formation and pseudo-outbreaks of M. chimaera through aerators.