Febrile gastroenteritis after eating on-farm manufactured fresh cheese – an outbreak of listeriosis?

Abstract

An outbreak of febrile gastroenteritis affected consumers of on-farm manufactured dairy products from a summer farm in Sweden. Symptoms included diarrhoea, fever, stomach cramps and vomiting in 88, 60, 54 and 21% of cases identified. The median incubation period was 31 h. A cohort study with 33 consumers showed an attack rate of 52% and an association between the total amount of product eaten and illness (P=0.07). Twenty-seven of 32 (84%) stool samples cultured for Listeria monocytogenes tested positive, although there was no association between clinical disease and the isolation of L. monocytogenes. In addition, gene sequences for VTEC and ETEC were detected in 6 and 1 subjects, respectively. Bacteriological analysis of cheese samples revealed heavy contamination with L. monocytogenes and coagulase positive staphylococci in all of them and gene markers for VTEC in one of them. Molecular profiles for L. monocytogenes isolated from dairy products, stool samples and an abscess from 1 patient who developed septic arthritis were identical. Results of both microbiological and epidemiological analyses point to L. monocytogenes as the most likely cause of this outbreak. The finding of markers for VTEC in some humans and cheese samples means that a mixed aetiology at least in some cases cannot be conclusively ruled out.

Increased In Vitro Adherence and On-Farm Persistence of Predominant and Persistent Listeria monocytogenes Strains in the Milking System

“…Several outbreaks of listeriosis have been linked to dairy products. These products include pasteurized milk (1,8,16), butter (33), on-farm-manufactured fresh cheese (7), and Mexican-style cheese (31,34).…”

Molecular Ecology of Listeria monocytogenes : Evidence for a Reservoir in Milking Equipment on a Dairy Farm

“…Dairy products have been identified as the source of several human listeriosis outbreaks (4,7,10,22). Listeria is ubiquitous on dairy farms (26), and it has been isolated from cows' feces, feed (3,26), and milk (21,35).…”

Biofilm formation by Listeria monocytogenes on stainless steel surface and biotransfer potential

“…Acquired through the ingestion of contaminated food, listeriosis can affect mainly immunocompromised individuals, the elderly, pregnant women and newborns (25). However, there are records of listeriosis outbreaks, characterized by gastrointestinal symptoms accompanied by fever, involving healthy individuals (7,18,31). Listeriosis manifests as febrile gastroenteritis (37), meningitis, encephalitis, mother-to-fetus infections and septicemia, resulting in death in 25-30% of cases (25).…”