Outbreak of an uncommon rifampicin resistant blaNDM-1Citrobacter amalonaticus strain in a digestive rehabilitation center: the putative role of rifaximin.

We describe a sudden two-week outbreak due to a blaNDM-1Citrobacter amaloniticus in a 22-bed digestive rehabilitation center. Three out of the five colonized patients received long-term rifaximin treatment to prevent hepatic encephalopathy. The strains were genotypically identical, phenotypically resistant to rifampin and harbored arr-3, a rifampin ADP-ribosyl transferase.