Mortality risk factors for listeriosis – A 10 year review of non-pregnancy associated cases in England 2006–2015

Listeriosis: is a foodborne illness that can result in septicaemia, Central Nervous System (CNS) disease, foetal loss and death in high risk patients. Objectives: To analyse the demographic trends, clinical features and treatment of non-perinatal listeriosis cases over a ten year period and identify mortality-associated risk factors. Methods: Reported laboratory-confirmed non-pregnancy associated cases of listeriosis between 2006 and 2015 in England were included and retrospectively analysed. Multivariate logistic regression analysis was performed to determine independent risk factors for mortality. Results: 1357/1683 reported cases met the inclusion criteria. Overall all-cause mortality was 28.7%; however, mortality rates declined from 42.1% to 20.2%. Septicaemia was the most common presentation 69.5%, followed by CNS involvement 22.4%. CNS presentations were significantly associated with age < 50 years, and septicaemia with older age. Age > 80 years (OR 3.32 95% CI 1.92–5.74), solid-organ malignancy (OR 3.42 95% CI 2.29-5.11), cardiovascular disease (OR 3.30 95% CI 1.64–6.63), liver disease (OR 4.61 95% CI 2.47–8.61), immunosuppression (OR 2.12 95% CI 1.40-3.21) and septicaemia (OR 1.60 95% CI 1.17–2.20) were identified as independent mortality risk factors. Conclusions: High risk groups identified in this study should be the priority focus of future public health strategies aimed at reducing listeriosis incidence and mortality.