A Mild Outbreak of Gastroenteritis in Long-Term Care Facility Residents Due to Clostridium perfringens, Australia 2009

Introduction: Clostridium perfringens food poisoning is a commonly cited cause of gastroenteritis outbreaks among elderly long-term care facility (LTCF) residents, yet little is known about the natural history of disease in this vulnerable group. In July 2009, an investigation into diarrheal illness among LTCF residents was commenced. Methods: An environmental health investigation and retrospective cohort study were undertaken to confirm the outbreak, to identify a source and mode of transmission, and to implement public health measures to prevent further cases. Menu listings and food safety program details were obtained and food-handling practices were observed. Clinical notes of all residents were reviewed. A possible case was defined as any resident developing one or more acute loose stool episodes between the evenings of 23 July and 27 July. Results: Fifty-two residents (41%) had been ill with diarrhea, and eight residents had fecal samples positive for C. perfringens enterotoxin. LTCF staff failed to perform routine temperature checks on hot foods before the outbreak. A sweet-and-sour pork lunch served on 23 July was implicated in causing residents' illness, but no residual food remained for microbiological testing. Independent associations with illness were demonstrated among residents living in two wings of the facility that received a standard level of service, whereas an inverse association with illness was shown among residents living in an "extra service" wing. Male residents were also more likely to become ill. Illness was mild with case patients reporting a median of two loose stools (range 1-12). Conclusions: C. perfringens is an important cause of both foodborne and nonfoodborne gastroenteritis outbreaks in LTCF, but may be missed due to the often mild nature of illness. This investigation highlights the potential burden of C. perfringens disease among vulnerable LTCF populations. To prevent C. perfringens outbreaks, facilities must adhere to food safety plans and ensure high standards of infection control practice.