Outbreak of Healthcare-associated Infection and Colonization with Multidrug-resistant Salmonella Enterica Serovar Senftenberg in Florida

Background: In July 1999, a rare strain of multidrug-resistant Salmonella enterica serovar Senftenberg was isolated from the sputum of a trauma patient. Over a 6-year period (1999-2005) in northeast Florida, this Salmonella serovar spread to 66 other patients in 16 different healthcare facilities as a result of frequent transfers of patients among institutions. To our knowledge, this is the first outbreak of healthcare-associated infection and colonization with a fluoroquinolone-resistant strain of S. Senftenberg in the United States.

Objectives: To investigate an outbreak of infection and colonization with an unusual strain of S. Senftenberg and assist with infection control measures.

Design: A case series, outbreak investigation, and microbiological study of all samples positive for S. Senftenberg on culture.

Setting: Cases of S. Senftenberg infection and colonization occurred in hospitals and long-term care facilities in 2 counties in northeast Florida.

Results: The affected patients were mostly elderly persons with multiple medical conditions. They were frequently transferred between healthcare facilities. This Salmonella serovar was capable of long-term colonization of chronically ill patients. All S. Senftenberg isolates tested shared a similar pulsed-field gel electrophoresis (PFGE) pattern.

Conclusion: A prolonged outbreak of infection and colonization with multidrug-resistant S. Senftenberg was identified in several healthcare facilities throughout the Jacksonville, Florida, area and became established when infection control measures failed. The bacterial agent was capable of long-term colonization in chronically ill patients. Because the dispersal pattern of this strain suggested a breakdown of infection control practices, a multipronged intervention approach was undertaken that included intense education of personnel in the different institutions, interinstitutional cooperation, and transfer paperwork notification.