Listeria monocytogenes and listeriosis Megan 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 www.bellenews.com Gellin et al 1989

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 Raw 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.

+   Transmission Etiologic agent Reservoir Leads to… Susceptible food Consumption of contaminated food

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 public www.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 Determine the burden of foodborne illness in the United States Monitor trends in the burden of specific foodborne illness over time Attribute the burden of foodborne illness to specific foods and settings Disseminate information that can lead to improvements in public health practice and the development of interventions to reduce the burden of foodborne illness. The network was established in July 1995 and is a collaborative program among CDC, 10 state health departments, the U.S. Department of Agriculture's Food Safety and Inspection Service (USDA-FSIS), and the Food and Drug Administration (FDA). FoodNet personnel located at state health departments regularly contact the clinical laboratories in Connecticut,Georgia, Maryland, Minnesota, New Mexico,Oregon, Tennessee and selected counties inCalifornia, Colorado, and New York to get reports of infections diagnosed in residents of these areas.  The surveillance area includes 15% of the United States population (46 million persons). FoodNet accomplishes its work through active surveillance; surveys of laboratories, physicians, and the general population; and population-based epidemiologic studies. Information from FoodNet is used to assess the impact of food safety initiatives on the burden of foodborne illness 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.lamarledger.com/ci_18902388?source=most_viewed http://www.cdc.gov/listeria/outbreaks/cantaloupes-jensen-farms/110211/index.html

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