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LISTERIA MONOCYTOGENES AND LISTERIOSISMegan Antosik, RD
Agenda
History Microbiology Related foods Infection Pathogenesis At-Risk
Populations
Diagnosis & Treatment
Outbreak History Current
Outbreaks Prevention
Objectives
After this presentation, audience members will be able to: Identify at-risk populations for contracting
Listeria monocytogenes. List 3 foods highly susceptible to
contamination of Listeria monocytogenes Describe the clinical characteristics used to
diagnose and identify listeriosis.
History
Hayem (France, 1891) & Henle (Germany, 1893)
Hulphers (Sweden, 1911) assigned the name Bacillus hepatitis
1919 - French clinicians preserved a diphtheroid isolated form of spinal fluid cultures of a patient with meningitis
1924 - Bacterium monocytogenes, named for the monocytosis it produced in rabbits
Gellin et al 1989
History
Lord Joseph Lister (1925) – Listerella hepatolytica
Nyfeldt (1929)
Listeria monocytogenes (1940)
Gellin et al 1989
Listeria
Seven species of Listeria Listeria monocytogenes Listeria ivanovii Listeria seeligeria Listeria welshimeri
Gellin et al 1989
Listeria monocytogenes
Facultative anaerobe ß-hemolytic Gram-positive Non-acid fast Non-sporulating linear rod Can grow at temperatures as low as 4°C Incubation period of 5-70 days
Gellin et al 1989
www.bellenews.com
L. monocytogenes
Sixteen serotypes Only 3 responsible for more than 90% of
human disease Serotype 4b Serotype 1/2b Serotype 1/2a
http://en.wikipedia.org/wiki/File:Serotypes_%E2%80%93_Antibody_versus_antigen.svg
Gellin et al 1989
L. monocytogenes
Ubiquitous in nature: Dust Soil Water Sewage Decaying vegetation
Animals can carry bacterium and transmit to food
www.zoenature.org
Gellin et al 1989
As a dietitian, what can we do? How would you protect against an
invader of this magnitude??
Susceptible Foods
Ready-to-Eat (RTE) foods Hot dogs Delicatessen meats Soft cheeses
Raw foods Meat Fruits Vegetables
Unpasteurized foods Milk and milk products
static.howstuffworks.com/gif/hot-dog-km.
+ Etiologic agent
Reservoir
Transmission
Susceptible food
Consumption of contaminated food
Leads to…
Listeriosis
Severe infection Consumption of foods contaminated by
L. monocytogenes Symptoms
Chills Fever Muscle aches Diarrhea Other GI symptoms
Pathogenesis
http://www.youtube.com/watch?v=mWjS3qDj6uw&feature=related
Intracellular pathogen Entry, growth, movement and spread in
a macrophage Phagocytosis Actin filaments “comet tail” Bypasses humoral immune system
Tilney et al 1989
Pathogenesis
At Risk?
In the United States, an estimated 1,600 persons become seriously ill with listeriosis each year. Of these, 260 die.
Older adults Pregnant women Newborns Immunocompromised
General publicwww.cdc.gov
Manifestations
Diagnosis of “invasive” listeriosis Symptoms include:
Headache Stiff neck Confusion Loss of balance Convulsions
www.cdc.gov
Listeriosis in Older Adults and the Immunocompromised
Host-dependent Septicemia Meningitis Death
Persons with AIDS: They are almost 300 times more likely to get listeriosis than people with normal immune systems.
www.cdc.gov
Listeriosis in Pregnant Women
Twenty times more likely to get listeriosis. About one in six (17%) cases occurs during pregnancy
Commonly experience mild “flu-like” symptoms
Infections: Still birth Miscarriage Premature delivery Life-threatening Infection of the newborn
www.cdc.gov
Diagnosis
Blood Cerebrospinal fluid (CSF) Amniotic fluid No stool or serological tests available
www.cdc.gov
Treatment
Most cases can spontaneously be cleared within 7 days
Otherwise - treated with IV antibiotics Ampicillin Bactrim
www.cdc.gov
Outbreak History
Outbreak History
What can we do?
Activate Listeria Initiative USDA FSIS & FDA “Zero Tolerance” policy Initiate the Healthy People objective
Achieve a 50% reduction in listeriosis incidence by 2010
2.5 cases per 1 million people
Voetsch et al 2007
How do we evaluate efficacy? Active surveillance studies 1996-2003 Foodborne Disease Active Surveillance
Network (FoodNet) Assess consumer practices
Voetsch et al 2007
http://www.cdc.gov/nationalsurveillance/PDFs/ListeriaCaseReportFormOMB0920-0004_alfalfa.pdf
http://www.cdc.gov/nationalsurveillance/PDFs/ListeriaCaseReportFormOMB0920-0004_alfalfa.pdf
What did we find?
N=766 isolates from 1996-2003 670 hospitalizations 153 fatalities 122 pregnant-associated cases
Voetsch et al 2007
Demographics
Crude Incidence 1996-2003
Did we achieve our goals?
Incidence of invasive listeriosis decreased by 24% Pregnancy-associated decreased by 37% Decrease of 23% in patients > 50 years old Crude incidence in 2003 was 3.1 cases per
1 million
Voetsch et al 2007
Are we in the clear?
www.cdc.gov/mmwr
Cantaloupe Outbreak 2011
Jensen Farms 146 affected 28 states 4 different strains 30 deaths 1 miscarriage Outbreak has officially ended
http://www.cdc.gov/listeria/outbreaks/cantaloupes-jensen-farms/110211/index.html
http://www.lamarledger.com/ci_18902388?source=most_viewed
http://www.cdc.gov/listeria/outbreaks/cantaloupes-jensen-farms/110211/map.html
http://www.cdc.gov/listeria/outbreaks/cantaloupes-jensen-farms/110211/timeline.html
What Went Wrong?
Inspectors ignored federal regulators FDA cited “serious design flaws” and
“lack of awareness” Bio Food Safety Auditing gave Jensen
Farms near perfect marks Jensen Farms did not have proper
chlorine or anti-bacterial wash Improper equipment
As dietitians, what can we do?
Prevention methods Food Safety
Cook foods thoroughly Prevent cross-contamination Buy pasteurized foods Proper sanitation Know where your food comes from Keep up-to-date on foodborne illness outbreaks
Regulation of food safety policies
http://www.foodsafety.gov/keep/index.html
Questions?
Don’t be afraid of food! Just play it safe!
www.gettyimages.com
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