1. Listeria Monocytogenes
Dr.T.V.Rao MD
Dr.T.V.Rao MD

2. What is Listeriosis
Listeriosis, a serious infection caused by eating food contaminated with the bacterium Listeria Monocytogenes, has recently been recognized as an important public health problem in the United States. The disease affects primarily persons of advanced age, pregnant women, new-borns, and adults with weakened immune systems. However, persons without these risk factors can also rarely be affected. 
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3. Listeria Monocytogenes is a rod-shaped aerobic and gram positive pathogenic bacterium that invades the cytoplasm of living cells. It develops a distinctive rocket tail structure to help push through the cytoplasm.  Eventually, these "rockets" push bacteria into neighboring cells, propagating the infection
Dr.T.V.Rao MD

4. Listeriosis
Listeriosis is caused by Bacterial agent an intracellular pathogen
Listeria Monocytogenes
L.monocytogenes produces infections world wide
Important cause of infections in animals and man.
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5. Who are at risk with Listeriosis
Pregnant women
New-borns
People with weakened immune systems
People who are taking immuno-suppressing medication.
Dr.T.V.Rao MD

6. Listeria Monocytogenes
L.monocytogenes is a Gram + ve non spore forming.
A specific character of the organism manifest with tumbling end or over end motility at
220c – 280c but not at
370c
But makes the Microbiologists to identify from Diptheriods, which are mistaken and specimens are discarded.
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7. Culture and Growth Characteristics
Grows on Muller Hinton agar with sheep blood as enrichment.
Small zone of Hemolysis can be observed around and the underneath of the colony.
Specimens are enriched if the tissues are kept at 40c and plated on the media
( Cold enrichment )
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8. Biochemical reactions
Bacteria are facultative anaerobic microbes
Catalase + motile
Listeria produce acid and not gas in various sugar fermentation tests
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9. Camp positive listeria
CAMP-positive Listeria monocytogenes inoculated at right angles to b-hemolytic Staphylococcus aureus. Note the arrow-shaped zone of weak enhanced hemolysis indicating a positive CAMP test. Gloves are worn when working with L. Monocytogenes. (Anne Hanson, University of Maine)
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10. How Humans contact Listeriosis
Listeria monocytogenes can be found in a variety of dairy products, vegetables, fish and meat products.
Listeria monocytogenes, unlike most other harmful bacteria, will grow slowly on foods stored in a refrigerator.
Listeria monocytogenes can also be spread by contact with an infected product or surface, such as hands or counter tops, during food preparation.
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11. Pathogenesis and Pathology
Listeria Monocytogenes enters through the Gastro – intestinal tract after infections of contaminated foods such as cheese or vegetables,
The cell wall surface protein called Interanalin interacts with E –CADHERIN and enters into epithelial cells
Bacteria produce Listeriolysin
L.monocygenes can move from cell to with out being exposed to Antibodies,Complement,Polymorphonuclear cells
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12. Who are at Higher Risk
The following conditions may be impaired with defective cell mediated Immunity
Pregnancy
AIDS
Lymphomas
Organ transplant recipients
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13. Contamination causes Listeriosis
Listeria Monocytogenes is found in soil and water.
Vegetables can become contaminated from the soil or from manure used as fertilizer.
Animals can carry the bacterium without appearing ill and can contaminate foods of animal origin such as meats and dairy products.
The bacterium has been found in uncooked meats and vegetables, soft cheeses, deli cold-cuts, and unpasteurized milk or foods.
If acquired at birth, the incubation period is 7 to 28 days.
The average incubation period is 31 days; with a range from 11 to 47 days.
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14. Symptoms Fever Muscle ache GI Sx: Nausea, diarrhea
Pregnant women: mild flu-like Sx, miscarriage, still birth, premature delivery, or infected newborn.
Lethargy
irritability
If infection spreads to the nervous system: headache, stiff neck, confusion, loss of balance, or convulsions.
Listeria can cause Pneumonia, Meningitis, and Sepsis.
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15. Common presenting manifestation of Listeriosis
Vomiting;
Nausea;
Cramps;
Diarrhea;
Severe Headache;
Constipation; or
Persistent fever.
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16. Listeriosis In Adults
Adults may present with bacterimia . Meingoencephalitis and occur most commonly in Immunosupressed patients in whom Listeria is one of the more common cause of Meningitis
Disease can be insidious to fulminant
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17. Listeriosis presenting with Meningitis
Immunocompromised adults are at risk for a serious infection of the blood stream and central nervous system (brain and spinal cord). Meningitis occurs in about half of the cases of adult Listeriosis. Symptoms of listerial meningitis occur about four days after the flu-like symptoms and include fever, personality change, uncoordinated muscle movement, tremors, muscle contractions, seizures, and slipping in and out of consciousness.
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18. Late onset manifestations
The new born child may present with late onset syndrome causes the development of Meningitis between birth and third week of life
It is often caused by serotype IV b and has a significant mortality rate
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19. Listeriosis and Pregnancy
Pregnant women - They are about 20 times more likely than other healthy adults to get Listeriosis. About one-third of listeriosis cases happen during pregnancy.
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20. Listeriosis in New Borns
New-borns - New- borns rather than the pregnant women themselves suffer the serious effects of infection in pregnancy.
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21. Diagnosis There is no routine screening test for susceptibility.
Patient may present with fever, or stiff nec, .
A blood or spinal fluid examination (to cultivate the bacteria) will confirm the clinical diagnosis. .
During pregnancy, patients need detailed investigations to rule our Listeriosis.

22. Diagnosis
Diagnosis dependent on isolation of Organisms in cultures obtained on CSF, Blood, and other fluids
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23. Treatment Listeriosis is a serious disease requiring hospitalization.
A combination of antibiotics is given intravenously through a small straw-like catheter.
When infection occurs during pregnancy, antibiotics must be given promptly to the mother to prevent infection of the fetus or newborn.
The duration of antibiotic treatment is at least 2 weeks.
Even with prompt treatment, some infections result in death.
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24. Antibiotic Treatment Ampicillin Erythromycin
Intravenous Trimethoprim – Sulphmethoxazole
Cephalosporins and Fluroquinoles are not active against l.monocytogens
A commination of Gentamycin and Ampicillin on clinical basis
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25. Foods to Avoid
Hot dogs, especially straight from the package without further heating. The fluid within hot dog packages may contain more Listeria than the hot dogs.
Avoid spreading fluid from packages onto other foods, cutting boards, utensils, dishes and food preparation surfaces. Wash your hands after handling hot dogs.
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26. Keep your food safe – avoid Listeriosis
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27. Ideal way to prevent Listeriosis
Completely cook all meats and eggs.
Carefully wash raw vegetables before eating.
Keep raw meat away from raw vegetables and prepared foods. After cutting raw meat, wash the cutting board with detergent before using it for vegetables.
Avoid drinking unpasteurized milk or foods made from such milk.
Wash hands thoroughly after handling raw meat.
Follow the instructions on food labels. Observe food expiration dates and storage conditions.
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28. Programme Created by Dr. T. V
Programme Created by Dr.T.V.Rao MD for Medical and Health Care Workers in the Developing World
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29. Referencec : www.slideshare.com
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