Candida krusei reservoir in a neutropaenia unit: molecular evidence of a foe?

Candida krusei has been documented as an emerging pathogen causing nosocomial outbreaks. The consecutive isolation of C. krusei strains in three patients admitted to the same hospital department within 2 months lead us to consider the possibility of an outbreak. Additionally, C. krusei isolates were collected from the room surfaces, whereas another isolate had been recovered from the blood of one patient 2 years before. HinfI DNA restriction endonuclease-based analysis of all C. krusei isolates was performed and restriction profiles were compared. Surprisingly, isolates from different patients were unrelated, whereas isolates from biological products of the same patient showed indistinguishable HinfI restriction patterns and were similar to those obtained from the surrounding environment of the respective patients. The study approach revealed the endogenous origin of the C. krusei infectious episodes observed and demonstrated that, subsequent to colonizing a patient, C. krusei can be involved in infectious episodes distant in time. The hypothesis of an outbreak was excluded, although we believe that the methodology employed in the present study represents a valuable tool for diagnostic and epidemiological surveys.