under the microscope
under the microscope
By Priya Dhagat , MS , MLS ( ASCP ) CM , CIC
A Growing List of Listeriosis : An Update on the Boar ’ s Head Deli Meat Outbreak
Listeria is an intracellular bacterium with unique virulence factors that allow it to survive and replicate in harsh conditions . It lives naturally in soil , water , and decaying vegetation . Farm animals can be asymptomatic carriers of Listeria which can contaminate the environment , various surfaces , farming equipment .”
Listeria infection is the third leading cause of foodborne illness in the United States . According to the CDC , about 1,600 people are infected with Listeria and 260 people die from the infection each year in the United States . There are numerous species of Listeria which are commonly found in the environment , but Listeria monocytogenes has historically been pathogenic and has caused numerous outbreaks over the past decade linked various products , such as Cotija cheese ( 2024 ), soybean sprouts ( 2023 ), and cantaloupe ( 2011 ).
Most recently , the national recall of several Boar ’ s Head deli products has made national headlines due to a deadly multi-state outbreak linked ready-to-eat liverwurst and deli meat products . On July 26 , 2024 , the Maryland Department of Health issued a health advisory for Boar ’ s Head products due to possible Listeria contamination after six cases were confirmed in Maryland on July 19 and a liverwurst sample collected by the Maryland Department of Health tested positive for L . monocytogenes . The product recall expanded on July 30 , recalling 7 million additional pounds of ready-to-eat meat and poultry products including 71 products produced between May 10 , 2024 , and July 29 , 2024 that were distributed nationwide and to the Cayman Islands , Dominican Republic , Mexico , and Panama . This is the second largest multistate outbreak of Listeria in over a decade with 57 hospitalized cases and nine deaths across 18 states as of August 27 , 2024 . Since some people are not tested and may recover without medical treatment , cases linked to this outbreak are likely higher .
The 2011 Listeria outbreak involving cantaloupe was the largest recorded multistate and was linked to a single Colorado farm leading to 147 cases in 28 states . The majority of patients were 60 years of age or older and were hospitalized and seven cases were among pregnant women and newborns .
But what leads to listeria outbreaks and why can it be difficult to control ? Let ’ s take a deeper look .
Listeria is an intracellular bacterium with unique virulence factors that allow it to survive and replicate in harsh conditions . It lives naturally in soil , water , and decaying vegetation . Farm animals can be asymptomatic carriers of Listeria which can contaminate the environment , various surfaces , farming equipment . Cross-contamination can occur during any point along the food production chain and into food-processing plants — during initial production , processing , distribution , or preparation — where it can persist for years by forming biofilms and adapting to and surviving in cold temperatures .
Once ingested , Listeria is able to resist stressful conditions in the gastrointestinal tract , such as the
Cross-contamination can occur during any point along the food production chain and into food-processing plants — during initial production , processing , distribution , or preparation — where it can persist for years by forming biofilms and adapting to and surviving in cold temperatures .”
acidic pH in the stomach and high osmolality in the gut . It invades the gastrointestinal tract and disseminates through the bloodstream to target certain organs , such as the liver and spleen , and can even cross the blood-brain-barrier and the placental barrier . Fever , flu-like symptoms , and intestinal symptoms may begin within two weeks after consuming contaminated products and may progress to invasive disease . Although listeriosis is usually a self-limiting gastrointestinal infection in healthy people , high risk populations for invasive infection include people who are pregnant , infants , immunocompromised individuals , and the elderly . Infection in people who are pregnant can lead to miscarriage , death of the unborn baby , a low-birth weight infant , health problems for the newborn , or even infant death .
Healthcare providers may refer to the CDC ’ s patient management framework here , which outlines considerations for testing and treatment . Standard precautions are recommended for patients who are hospitalized , as person-to-person transmission is rare . Click here to stay updated with this current outbreak and view case numbers and US states affected . Read more about Listeria here :
https :// www . fda . gov / animal-veterinary / animal-health-literacy / get-facts-aboutlisteria # recalls https :// www . sciencedirect . com / science / article / abs / pii / S0956713520304564
Priya Dhagat , MS , MLS ( ASCP ) CM , CIC , is an infection preventionist and the associate director of the system-wide Special Pathogens Program within the Department of Emergency Management at New York City Health + Hospitals , overseeing special pathogen preparedness and response efforts across New York City Health + Hospitals frontline healthcare facilities . Additionally , she supports and offers subject matter expertise for infection prevention topics for the National Emerging Special Pathogens Training and Education Center ( NETEC ).
8 • www . healthcarehygienemagazine . com • september 2024