Pseudo-outbreak of Pseudomonas mendocina in stem cell cultures

Pseudomonas mendocina was first isolated in the 1970s from soil and water samples collected in the province of Mendoza, Argentina. Its recovery from human clinical specimens other than urine and leg ulcers was not documented until 1992, when a case report of an endocarditis caused by P. mendocina was published. We report the detection of P. mendocina in diagnostic stem cell cultures in the haematology unit, which initiated an outbreak investigation after identification of P. mendocina from three diagnostic stem cell cultures. Culture of a reagent used for the preparation of the diagnostic stem cell cultures revealed P. mendocina. Further outbreak investigation at the manufacturing site confirmed contamination of the product. This is the first report of an outbreak caused by P. mendocina from a commercial 'sterile' product. We conclude that this environmental pathogen has the potential to cause contamination of reagents used in clinical settings. Detection of P. mendocina should alert hospital personnel to possible product contamination.