Evidence map›Paper›PMID 39979856›Full record

ArticleBMC infectious diseases2025

Key role of whole genome sequencing in resolving an international outbreak of monophasic Salmonella Typhimurium linked to chocolate products.

Valeska Laisnez, Amoolya Vusirikala, Charlotte Salgaard Nielsen, Vera Cantaert, Laurence Delbrassinne, Wesley Mattheus, Bavo Verhaegen, Hugues Delamare, Nathalie Jourdan-Da Silva, Raskit Lachmann and 15 more

Abstract read
In one paragraph

Article in BMC infectious diseases, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 6 papers.

0numbers the graph read from it
0cells of the map it votes in
6citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

6 citing papers in PubMed.

  1. The 2026New microbes and new infections · 2026
    Article
  2. Article
  3. Article
  4. Review
  5. The European Union One Health 2024 Zoonoses Report.EFSA journal. European Food Safety Authority · 2025
    Article
  6. Phylogeny and divergence of the 100 most commonFrontiers in microbiology · 2025
    Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

25 authors.

Valeska LaisnezDepartment of Epidemiology and Public Health, Sciensano, Brussels, Belgium.
Amoolya VusirikalaField Service South-East and London, Health Protection Operations Division, UK Health Security Agency, London, England, United Kingdom.
Charlotte Salgaard NielsenECDC Fellowship Programme, Field Epidemiology path (EPIET), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden.
Vera CantaertFederal Agency for the Safety of the Food Chain, Brussels, Belgium.
Laurence DelbrassinneNational Reference Laboratory for Foodborne Outbreaks, Sciensano, Brussels, Belgium.
Wesley MattheusNational Reference Centre for Salmonella and Shigella, Sciensano, Brussels, Belgium.
Bavo VerhaegenNational Reference Laboratory for Foodborne Outbreaks, Sciensano, Brussels, Belgium.
Hugues DelamareDirection des maladies infectieuses, Santé publique France, Saint-Maurice, France.
Nathalie Jourdan-Da SilvaDirection des maladies infectieuses, Santé publique France, Saint-Maurice, France.
Raskit LachmannRobert Koch Institute, Department of Infectious Disease Epidemiology, FG 35 - Gastrointestinal Infections, Zoonoses and Tropical Infections, Berlin, Germany.
Sandra SimonRobert Koch Institute, Department of Infectious Diseases, Unit for Enteropathogenic Bacteria and Legionella/ National Reference Centre for Salmonella and other Bacterial Enterics, Wernigerode, Germany.
Martin CormicanSchool of Medicine, University of Galway, Galway, Ireland.
Patricia GarveyHealth Protection Surveillance Centre, Health Service Executive, Dublin, Ireland.
Paul McKeownNational Salmonella, Shigella and Listeria Reference Laboratory, Galway, Ireland.
Roger StephanInstitute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zürich, Zurich, Switzerland.
Derek BrownScottish Microbiology Reference Laboratories, Glasgow, United Kingdom.
Lynda BrowningPublic Health Scotland, Glasgow, United Kingdom.
Ann HobanGastrointestinal Infections and Food Safety (One Health) Division, Clinical and Public Health Group, UK Health Security Agency, London, England, United Kingdom.
Lesley LarkinGastrointestinal Infections and Food Safety (One Health) Division, Clinical and Public Health Group, UK Health Security Agency, London, England, United Kingdom.
S. Typhimurium Outbreak Investigation Group
Maria Pardos de la GandaraInstitut Pasteur, Université Paris Cité, Unité des Bactéries pathogènes entériques, Centre National de Référence des Escherichia coli, Shigella et Salmonella, Shigella et Salmonella, Paris, France.
Cecilia JernbergEuropean Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden.
Johanna TakkinenEuropean Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden.
Sooria BalasegaramGastrointestinal Infections and Food Safety (One Health) Division, Clinical and Public Health Group, UK Health Security Agency, London, England, United Kingdom.
Dieter Van CauterenDepartment of Epidemiology and Public Health, Sciensano, Brussels, Belgium. dieter.vancauteren@sciensano.be.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundIn February 2022, the United Kingdom (UK) detected a cluster of monophasic Salmonella Typhimurium based on whole genome sequencing (WGS). Subsequently, several countries reported cases belonging to this cluster. Epidemiological, microbiological and traceability investigations pointed toward a chocolate food business operator (FBO) in Belgium. We describe the magnitude of the outbreak, investigations performed and control measures taken.

methodsCases were ascertained based on internationally agreed case definitions and interviewed about food consumption prior to disease onset. Analytical epidemiological studies were conducted by the UK and Ireland. The Belgian food safety authority (FSA) coordinated microbiological and traceability investigations.

resultsA total of 456 cases (61% female), belonging to two genetically different WGS clusters, in 14 countries of the European Union, the UK, Switzerland, Canada and the United States were linked to the outbreak, between December 2021 and June 2022. 87% of cases were younger than 10 years. Brand A chocolate eggs, marketed for children, were reported as consumed by 168 cases (80%) with information. Analytical studies in the UK and Ireland showed a significantly higher odds of disease associated with consumption of brand A chocolate products. Retrospective investigations by the FSA revealed that routine samples (raw materials, intermediate, semi-finished and finished products as well as environmental and rinse oil samples) taken by the FBO linked to the Brand A products between December 2021 and January 2022 had tested positive for salmonella. Nine isolates were submitted to EnteroBase and matched with human isolates from both WGS clusters. The authorization for production was temporarily withdrawn on 8 April 2022 and all products of brand A were recalled worldwide, followed by a decrease in cases.

conclusionsA multi-country salmonellosis outbreak linked to chocolate occurred in the months before Easter 2022. International collaboration between stakeholders from epidemiological, microbiological and food safety entities with rapid sharing of WGS results from human and nonhuman isolates were key in containing the outbreak. Implementation of routine WGS on human and nonhuman isolates will strengthen public health responses to future outbreaks. The magnitude of the outbreak underlines the importance of timely and open communication of FBOs to FSAs in case of salmonella detection.

Indexed as

ChocolateDisease OutbreaksSalmonella Food PoisoningSalmonella typhimuriumWhole Genome SequencingAdolescentAdultAgedChildChild, PreschoolFemaleFood MicrobiologyHumansInfantIrelandMaleChocolate productsMonophasic Salmonella TyphimuriumOutbreakSalmonellosisWhole genome sequencing

Identifiers

PMID39979856
PMCPMC11844163

What OpenQuestion holds

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LicenceCC BY-NC-ND
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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.