{"id":5219,"date":"2025-09-03T00:24:12","date_gmt":"2025-09-03T06:24:12","guid":{"rendered":"https:\/\/allphasepharma.com\/dir\/?p=5219"},"modified":"2025-09-12T14:18:03","modified_gmt":"2025-09-12T20:18:03","slug":"listeria-food-recalls-outbreaks-and-resistance","status":"publish","type":"post","link":"https:\/\/allphasepharma.com\/dir\/2025\/09\/03\/5219\/listeria-food-recalls-outbreaks-and-resistance\/","title":{"rendered":"LISTERIA: Food Recalls, Outbreaks, and Resistance"},"content":{"rendered":"

\"\"<\/a>You may be aware of recent food product recalls associated with food poisoning due to listeria contamination: ready-to-eat products, deli meats, sandwiches, protein snacks, chicken, turkey, cheese and dairy products.\u00a0 The list is long as Listeria is ubiquitous in the environment.\u00a0 One can find it in meat and milk\/cheese products mainly, but it does not end there, as recent outbreaks testify.\u00a0 Sometimes it\u2019s blueberries, sometimes contaminated lettuce, celery or hummus, your favorite Middle Eastern dish.\u00a0 This list keeps getting longer. [1]<\/a><\/p>\n

Here is a graphic that shows food recalls over the past 10 years for the 3 main pathogens:<\/p>\n

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Figure 1: From Ref. [2]<\/strong><\/a><\/p>\n

For 2025, a similar picture emerges.\u00a0 As of August, according to the Food Recall Reporter, we had 33 recalls of products just in the US due to Listeria contamination [3]<\/a>.\u00a0 This website details food recalls not only by pathogen but also by Recall Class<\/strong> which is defined as:<\/p>\n

Class I: Most serious, involving products that may seriously harm or kill a consumer.<\/strong><\/span>
\nClass II: Potential health hazard with a remote probability of adverse health consequences.<\/span>
\nClass III: Products that may pose a risk to specific (but not all) consumers.<\/strong><\/p>\n

\"\"<\/a><\/p>\n

Of all the recalls due to bacterial contamination found in this extensive database, Salmonella and Listeria were by far the leading offenders.\u00a0 Most recalls were in the most serious Class 1 category.\u00a0 The number of actual outbreaks is not searchable in Food Recall Reporter but actual outbreaks are presumably less frequent than the number of Public Health Alerts.<\/p>\n

Listeria infection is a reportable disease. Despite so many recalls and the high prevalence of the organism in veterinary medicine and food products, outbreaks are rather infrequent. Telling by the recent literature, it seems that veterinarians are studying the organism more than clinicians who see relatively few infections caused by Listeria monocytogenes, because we have infection control measures in place that prevent transmission with a very high degree of success.<\/p>\n

Listeria is a pathogen that commands respect.\u00a0 It is associated with higher mortality than Salmonella infection.\u00a0 When bloodstream infections occur in immunocompromised patients, the mortality is very high even with appropriate antibiotic therapy (30-40%).\u00a0 The CDC estimates that listeriosis is the third leading cause of death from foodborne illnesses with about 260 deaths per year.[4]<\/a>, [5]<\/a><\/p>\n

It demonstrates some really effective and novel ways of overcoming host barriers and defense systems.<\/p>\n

Listeriosis, as is often stated, is an infection of the very young, pregnant women, older persons and those with significant immune defects.\u00a0 Isolation from patients often comes as a surprise.\u00a0 A call from the micro lab about a variable gram-positive organism, with tumbling motility may be the first hint that we are dealing with this pathogen.\u00a0 Hopefully, there will be no second call from the micro lab telling us about an unanticipated resistance pattern.<\/p>\n

The latest and 10th edition of Mandell\u2019s PPID[6]<\/a> still lists ampicillin and gentamicin as the antibiotics of choice.\u00a0 This is correct now but may not be so much longer.<\/p>\n

In veterinary medicine, isolates resistant to multiple antibiotics have almost routinely been found.\u00a0 By now, most L. monocytogenes strains are tetracycline, cephalosporin, and quinolone resistant.\u00a0 The frequent presence of resistance to disinfectants and metal ions would seem to be the result of wide-spread indiscriminate antibiotic use in farming and veterinary practice. Chromosomal and plasmid-mediated resistance, efflux pumps and other mechanisms\u00a0 make Listeria an MDR pathogen and more capable invader.[7]<\/a>\u00a0 Resistance to meropenem, aminoglycosides and trimethoprim, antibiotics often used in the clinic, are particularly of concern [8]<\/a>, [9]<\/a>.\u00a0 Plasmids encoding resistance to chloramphenicol, clindamycin, erythromycin, streptomycin, and tetracycline have been documented.[10]<\/a><\/p>\n

It stands to reason that MDR isolates found in food sources will eventually be seen in human cases as well.<\/p>\n

It is hard to find susceptibility data on clinical isolates from the USA.\u00a0 While the literature is replete with data from China to Iran, Brazil to Russia, amazingly little is published about the antibiogram of listeria from US patients and outbreaks.\u00a0 Unfortunately, the last 10-year report on ‘Foodborne Illness in the US’ is from 2019, and it does not provide susceptibility information.5<\/sup><\/p>\n

Here is our take on the Listeria landscape, a mix of known facts and a few new insights:<\/p>\n