Surveillance Plan for L. Monocytogenes Post a Hospital Kitchen Outbreak

Abstract

Background Listeria monocytogenes is a serious infection that is especially dangerous for the immunocompromised patient population. In the hospital kitchen environment, there are many opportunities for introduction and contamination of food contact surfaces which can lead to transmission to patients. Following a November 2019 clinical outbreak of L. monocytogenes with concurrent positive cultures in our hospital kitchen, the Infection Control Department at a tertiary cancer center created a cohesive surveillance strategy. Methods Immediately following the conclusion of outbreak mitigation, the Infection Control Department, in accordance with the New York State Department of Health, performed biweekly environmental sampling of the kitchen. Environmental samples were collected over 6 months, using sponge swabs that were tested by polymerase chain reaction (PCR) and microbiologic culturing. Additionally, our Infection Control and Environmental Services Departments partnered to review and revise cleaning and disinfection methods. Results At the end of the 6-month environmental surveillance, there were no positive environmental samples. Thereafter, testing frequency was reduced to monthly. A total of 504 environmental samples, including food contact and non-food contact surfaces, were collected. Only 2 swabs have resulted in positive cultures for L. monocytogenes, both non-contact, and neither were linked to any clinical infections. The kitchen cleaning protocol was overhauled with increased frequency of deep cleaning, identification and inclusion of overlooked areas, and acquisition of new and improved products (with activity against L. monocytogenes) and cleaning equipment. Conclusions Continued environmental sampling of a hospital kitchen provides an effective way to ensure patients are not exposed to potentially severe foodborne illnesses, such as Listeria monocytogenes, and keeps a keen focus on hospital wide-infection control practices. Coordination and collaboration with interdisciplinary departments is essential to provide continued focus on risk mitigation in the complex hospital kitchen environment. Listeria monocytogenes is a serious infection that is especially dangerous for the immunocompromised patient population. In the hospital kitchen environment, there are many opportunities for introduction and contamination of food contact surfaces which can lead to transmission to patients. Following a November 2019 clinical outbreak of L. monocytogenes with concurrent positive cultures in our hospital kitchen, the Infection Control Department at a tertiary cancer center created a cohesive surveillance strategy. Immediately following the conclusion of outbreak mitigation, the Infection Control Department, in accordance with the New York State Department of Health, performed biweekly environmental sampling of the kitchen. Environmental samples were collected over 6 months, using sponge swabs that were tested by polymerase chain reaction (PCR) and microbiologic culturing. Additionally, our Infection Control and Environmental Services Departments partnered to review and revise cleaning and disinfection methods. At the end of the 6-month environmental surveillance, there were no positive environmental samples. Thereafter, testing frequency was reduced to monthly. A total of 504 environmental samples, including food contact and non-food contact surfaces, were collected. Only 2 swabs have resulted in positive cultures for L. monocytogenes, both non-contact, and neither were linked to any clinical infections. The kitchen cleaning protocol was overhauled with increased frequency of deep cleaning, identification and inclusion of overlooked areas, and acquisition of new and improved products (with activity against L. monocytogenes) and cleaning equipment. Continued environmental sampling of a hospital kitchen provides an effective way to ensure patients are not exposed to potentially severe foodborne illnesses, such as Listeria monocytogenes, and keeps a keen focus on hospital wide-infection control practices. Coordination and collaboration with interdisciplinary departments is essential to provide continued focus on risk mitigation in the complex hospital kitchen environment.