Multinational Outbreak of Listeria monocytogenes Infections Linked to Enoki Mushrooms Imported from the Republic of Korea 2016-2020.

Keeping the global food supply safe necessitates international collaborations between countries. Health and regulatory agencies routinely communicate during foodborne illness outbreaks, allowing partners to share investigational evidence. A 2016-2020 outbreak of Listeria monocytogenes infections linked to imported enoki mushrooms required a multinational collaborative investigation among the United States, Canada, Australia, and France. Ultimately, this outbreak included 48 ill people, 36 in the United States and 12 in Canada, and was linked to enoki mushrooms sourced from one manufacturer located in the Republic of Korea. Epidemiologic, laboratory, and traceback evidence led to multiple regulatory actions, including extensive voluntary recalls by three firms in the United States and one firm in Canada. In the United States and Canada, the Korean manufacturer was placed on import alert while other international partners provided information about their respective investigations and advised the public not to eat the recalled enoki mushrooms. The breadth of the geographic distribution of this outbreak emphasizes the global reach of the food industry. This investigation provides a powerful example of the impact of national and international coordination of efforts to respond to foodborne illness outbreaks and protect consumers. It also demonstrates the importance of fast international data sharing and collaboration in identifying and stopping foodborne outbreaks in the global community. Additionally, it is a meaningful example of the importance of food sampling, testing, and integration of sequencing results into surveillance databases.

Multistate Outbreak of Listeria monocytogenes Infections Linked to Fresh, Soft Hispanic-Style Cheese - United States, 2021.

Listeriosis is a serious infection usually caused by eating food contaminated with the bacterium Listeria monocytogenes. An estimated 1,600 persons become ill with listeriosis each year, among whom approximately 260 die. Persons at higher risk for listeriosis include pregnant persons and their newborns, adults aged ≥65 years, and persons with weakened immune systems. Persons with invasive listeriosis usually report symptoms starting 1-4 weeks after eating food contaminated with L. monocytogenes; however, some persons who become infected have reported symptoms starting as late as 70 days after exposure or as early as the same day of exposure (1). On January 29, 2021, PulseNet, the national molecular subtyping surveillance network coordinated by CDC, identified a multistate cluster of three L. monocytogenes infections: two from Maryland and one from Connecticut (2). CDC, the Food and Drug Administration (FDA), and state and local partners began an investigation on February 1, 2021. A total of 13 outbreak-related cases were eventually identified from four states. All patients reported Hispanic ethnicity; 12 patients were hospitalized, and one died. Rapid food testing and record collection by regulatory agencies enabled investigators to identify a brand of queso fresco made with pasteurized milk as the likely source of the outbreak, leading to an initial product recall on February 19, 2021. Fresh, soft Hispanic-style cheeses made with pasteurized milk are a well-documented source of listeriosis outbreaks. These cheeses can be contaminated with L. monocytogenes unless stringent hygienic controls are implemented, and the processing environment is monitored for contamination (3). U.S. public health agencies should establish or improve communications, including new methods of disseminating information that also effectively reach Hispanic populations, to emphasize the risk from eating fresh, soft Hispanic-style cheeses, even those made with pasteurized milk.

Septicaemic Listeriosis in a White-Faced Saki (Pithecia pithecia).

A 27-year-old female white-faced saki (Pithecia pithecia) died following an onset of vomiting and ptyalism. Necropsy revealed lesions of suppurative ventriculitis, choroid plexitis, periventricular encephalitis and meningitis with intralesional gram-positive coccobacilli and paired rods. The saki also had suppurative to mononuclear hepatitis, mild intestinal crypt necrosis, proliferative glomerulonephritis, aortic arteriosclerosis, pulmonary interstitial fibrosis, chronic mild epicarditis, ovarian medullary arteriopathy and a focal superficial cerebral fibrotic nodule with surrounding chronic mixed cell inflammation. Listeria monocytogenes was cultured from liver and spinal cord. Intralesional Listeria bacteria were immunolabelled in brain sections and real-time polymerase chain reaction of brain tissue detected L. monocytogenes. Whole genome multilocus sequence typing characterized the cultured bacterial isolates as sequence type 6 and clonal complex 6. A database search for related clinical and food listerial outbreaks identified genetically related isolates but, because these isolates were more than 20 alleles distant from the saki isolates, they were not a related cluster. Reports of listeriosis in non-human primates are infrequent, and when infections do occur, they tend to be haematogenous with the propensity to cause meningoencephalitis. This saki likely ingested environmental L. monocytogenes, which resulted in disease that may have been facilitated by pre-existing co-morbidities and age.

Evaluation of Avocados as a Possible Source of Listeria monocytogenes Infections, United States, 2016 to 2019.

ABSTRACT: Outbreaks of Listeria monocytogenes infections have historically been associated with contaminated deli meats, but recent outbreaks have been linked to produce. To date, avocados have not been identified as the source of any outbreaks of L. monocytogenes infections in the United States, but avocado samples have yielded strains that were closely related genetically to clinical L. monocytogenes isolates. To determine whether avocados have been a source of listeriosis, we conducted a retrospective review of epidemiological data for clinical isolates that were genetically related to isolates from avocados. Using a national database, we identified clusters containing clinical and at least one avocado isolate. We then selected clusters based upon isolation dates, cluster and composition size, and available food history data. For each cluster, we assessed (i) whether avocado consumption was higher among case patients in the cluster than among those with sporadic illnesses and (ii) whether the only food isolates within the cluster were from avocados. If both conditions were met, the link was considered "likely," if one condition was met the link was considered "possible," and if neither condition was met evidence was "limited." Five of 15 clusters met the criteria for assessment. Of these, two were classified as having "limited" evidence for a link to avocados, two as "possible," and one as "likely." For the cluster considered "likely," avocado consumption was significantly higher among case patients in the cluster compared with sporadic illnesses (odds ratio, 8.5; 95% confidence interval, 1.5 to 86.5). We identified three clusters that were likely or possibly linked to avocados, which suggests that avocados could be a source of listeriosis in the United States. Messaging on safe handling might be warranted for groups at higher risk, but further research is first needed to better characterize the ecology of pathogens on avocados and the likelihood of internalization of L. monocytogenes.

Corrigendum: Whole Genome Sequencing: Bridging One-Health Surveillance of Foodborne Diseases.

[This corrects the article DOI: 10.3389/fpubh.2019.00172.].

Whole Genome Sequencing: Bridging One-Health Surveillance of Foodborne Diseases.

Infections caused by pathogens commonly acquired from consumption of food are not always transmitted by that route. They may also be transmitted through contact to animals, other humans or the environment. Additionally, many outbreaks are associated with food contaminated from these non-food sources. For this reason, such presumed foodborne outbreaks are best investigated through a One Health approach working across human, animal and environmental sectors and disciplines. Outbreak strains or clones that have propagated and continue to evolve in non-human sources and environments often show more sequence variation than observed in typical monoclonal point-source outbreaks. This represents a challenge when using whole genome sequencing (WGS), the new gold standard for molecular surveillance of foodborne pathogens, for outbreak detection and investigation. In this review, using recent examples from outbreaks investigated in the United States (US) some aspects of One Health approaches that have been used successfully to solve such outbreaks are presented. These include using different combinations of flexible WGS based case definition, efficient epidemiological follow-up, traceback, surveillance, and testing of potential food and environmental sources and animal hosts.

Outbreak of Salmonella Chailey Infections Linked To Precut Coconut Pieces - United States and Canada, 2017.

Foodborne salmonellosis causes an estimated 1 million illnesses and 400 deaths annually in the United States (1). In recent years, salmonellosis outbreaks have been caused by foods not typically associated with Salmonella. On May 2, 2017, PulseNet, CDC's national molecular subtyping network for foodborne disease surveillance, identified a cluster of 14 Salmonella Chailey isolates with a rare pulsed-field gel electrophoresis (PFGE) pattern. On May 29, Canadian health officials informed CDC that they were also investigating a cluster of five Salmonella Chailey infections in British Columbia with the same PFGE pattern. Nineteen cases were identified and investigated by CDC, U.S. state health departments, the Public Health Agency of Canada, and the British Columbia Centre for Disease Control. Isolates from all cases were highly related by whole genome sequencing (WGS). Illness onset dates ranged from March 10 to May 7, 2017. Initial interviews revealed that infected persons consumed various fresh foods and shopped at grocery chain A; focused questionnaires identified precut coconut pieces from grocery chain A as a common vehicle. The Canadian Food Inspection Agency (CFIA) and the U.S. Food and Drug Administration (FDA) conducted a traceback investigation that implicated a single lot of frozen, precut coconut as the outbreak source. Grocery chain A voluntarily removed precut coconut pieces from their stores. This action likely limited the size and scope of this outbreak.