A recent edition of the Centers for Disease Control MMWR report* documented the role of intestinal Salmonella carriers in a protracted intermittent outbreak of Salmonella Mbandaka.  Cases were first identified in Michigan in 2008 but extending through 2018.  Pathogens from thirty-six patients were subjected to initially pulse-field gel electrophoresis and more recently whole genome sequencing. 

The Michigan Department of Health and Human Services in collaboration with the Kalamazoo County Health and Community Services Department interviewed patients and collected specimens over a ten-year period leading to identification of a specific restaurant as the source of outbreaks.  Salmonella Mbandaka was isolated from the environment of the restaurant and stool specimens from asymptomatic workers. 

The publication emphasizes the need for routine Salmonella monitoring of employees to confirm freedom from intestinal Salmonella colonization as is required in many nations of the EU.  Obviously, food handlers in restaurants should be screened as part of any investigation of a foodborne disease outbreak.

*Nettleton, W.D. et al protracted intermittent outbreak of Salmonella Mbandaka linked to a restaurant in Michigan 2008-2019.  MMWR Morb. Mortal. Wkly. Rep. 70:1109-1113 (2021)