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!

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