This slide explains abot listeriosis and their effect on human body. And also about the History, Types - both invasive and non-invasive, Pathogenisis, Diagnosis, Clinical manifestation,Treatment and Control methods.

1. L I S T E R I O S I S A N D T H E I R E F F E C T
O N H U M A N H E A LT H
O V YA P U G A L E N T H I A R U N A

2. C O N T E N T
• Listeriosis
• History
• The disease
• Microbiology
• Pathogenesis
• Diagnosis

3. C O N T… .
• Clinical manifestation
• Treatment
• Control methods
• Detection of food-born pathogens
• Prevention
• Bibliography

4. L I S T E R I O S I S
• Listeriosis is a bacterial
infection most commonly
caused by Listeria
monocytogenes.

6. H I S T O RY
• In 2002 a seven-state
listeriosis outbreak was
linked to deli meats and
hot dog produced at a
single meat processing
plant in United States .
Microbiologist matched
the strain of
L.monocytogenes found in
the contaminated food
products with samples
obtained from floor drains
in packaging plant.

7. • This episode promoted the U.S. Department of
Agriculture (USDA) to step up its environmental
testing program for L.monocytogene.
• In 2006 the U.S.food and drug administration
approved a new approach to prevent listeriosis:
spraying virus that attack and destroy the bacterium
on ready-to-eat cold cuts and meats. In other words
these viruses are food additives. This method is safe
because the virus only attack L. Monocytogenes,not
human cell.

8. - N O N - I N VA S I V E F O R M
- I N VA S I V E F O R M
T H E R E A R E T W O T Y P E S O F
L I S T E R I O S I S

9. N O N - I N VA S I V E F O R M
• Also known as febrile listerial gastroenteritis.
• A mild form of the disease affecting mainly otherwise healthy people.
• Symptoms include :
1. Diarrhoea,
2. Fever,
3. Headache, and
4. Myalgia (muscle pain).
• The incubation period is short (a few days).
• Outbreaks of this disease have generally involved the ingestion of foods
containing high doses of L. monocytogenes.

10. I N VA S I V E F O R M
• A more severe form of the disease and affects certain high risk groups of the
population.
• These include pregnant women, patients undergoing treatment for cancer, AIDS and
organ transplants, elderly people and infants. This form of disease is characterised by
severe symptoms and a high mortality rate (20%–30%).
• Symptoms include:
1.Fever
2.Myalgia
3.Septicemia and
4.Meningitis.
• The incubation period is usually one to two weeks but can vary between a few days
and up to 90 days.

11. M I C R O B I O L O G Y ( L . M O N O C Y T O G E N E S )
• Facultative anaerobic.
• Non-sporulating.
• Gram-positive rod.
• Temperature and salt tolerant.
• Motile during growth at low temperatures.(much less than
37degree Celsius)
• Human listerial diseases serotypes -1/2a, 1/2b, and
4.L.monocytogenes - weekly β-hemolytic on blood agar.

12. PAT H O G E N E S I S

13. • Infection with L.monocytogenes follow
ingestion of contaminated food that
contains the bacteria at high
concentration.
• Its entry into cell is mediated by host
surface protein classified as internalins.
• LLO is spore forming, cholesterol
dependent cytolysis. Which is
responsible for mediating the rupture of
the phagosomal membrane.
• Once in cytosol L. Monocytogenes
grow very rapidly. (a PrfA- regulated
genes encode hexose-phosphate
transporter that facilitates the growth of
bacteria)
• After exposure to mammalian-cell
cytosol L.monocytogenes produce
another PrfA- regulated surface protein.

14. • ActA mimics host protein
of the Wiskott-Aldrich
syndrome protein (WASP)
family by promoting the
actin nucleation properties
of the Arp2/3 complex.
Thus L.monocytogenes
can enter the cytosine of
almost any eukaryotic cell
and can exploit a
conserved and essential
actin- based morality
system. ( cell-to-cell spread
without exposure to the
extracellular milieu.) (ActA)

15. D I A G N O S I S
• Based on clinical symptoms
• Detection of the bacteria in a smear from
1. Blood,
2. Cerebrospinal fluid (CSF),
3. Meconium of newborns (or the foetus in abortion
cases), as well as from faeces, vomitus, foods or animal
feed.
• Various detection methods, including polymerase chain reaction (PCR), are available
for diagnosis of listeriosis in humans.
• During pregnancy, blood and placenta cultures are the most reliable ways to discover
if symptoms are due to listeriosis.

16. • Gastroenteritis : develops within
48 hr of ingestion. Manifestation
includes fever, diarrhoea,
headache, and constitutional
symptoms.
• Bacteraemia : present with fever,
chills and myalgia/arthralgia.
Meningeal symptoms, focal
neurologic findings, or mental
status changes may suggest the
diagnosis. Flu like illness in
pregnant women. Endocarditis of
valves.( both prosthetic and
native)
Clinical manifestation

17. • Meningitis : present with fever and headache followed by
asymmetric cranial nerve deficits, cerebellar signs, and hemiparetic
and hemisensory deficits.
Respiratory failure can occur.
The CSF profile in listerial meningitis often shows WBC counts in
the range 100-5000/µL. Low glucose levels.
• Other focal infections: infection of visceral organs - the eye, the
pleural, peritoneal, and pericardial spaces, and the bones and joints
have all been reported.
• Listeriosis in pregnancy is usually presented with nonspecific acute
or subacute febrile illness with myalgia, arthralgia, backache, and
headache.
Prepartum treatment of bacteraemic mother enhance the chance of
delivery of a healthy infant.
Mortality rates are much lower in Live-born neonates treated with
antibiotics.

19. T R E AT M E N T
• Listeriosis can be treated if diagnosed early. Antibiotics are used to treat severe symptoms such as
meningitis.
• When infection occurs during pregnancy, prompt administration of antibiotics prevents infection of the
foetus or newborn.
• Ampicillin is drug of choice, adults should receive IV at high doses (2mg every 4h)
• Erythromycin
• Trimethoprim - sulphmethoxazole (intravenously) is an alternative for penicillin-allergic patients
(15-20 mg of TMP/kg per day) in divided dose every 6-8 h.
• Combination of gentamicin and ampicillin for synergy (1.0-1.7 mg/kg every 8 hr). Neonates should
receive at a dose based on weight.
• The duration of therapy depends on the syndrome:
A. Bacteremia - 2 weeks
B. Meningitis - 3 weeks
C. Brain absess/encephalitis - 6-8 weeks
D. Endocarditis - 4-6 weeks (both adults and neonates)

20. C O N T R O L M E T H O D S
• The control of L. monocytogenes is required at all
stages in the food chain and an integrated approach is
needed to prevent the multiplication of this bacteria in
the final food product.
• The challenges for controlling L. monocytogenes are
considerable given its ubiquitous nature, high resistance
to common preservative methods, such as the use of
salt, smoke or acidic condition in the food, and its ability
to survive and grow at refrigeration temperatures
(around 5 °C).

21. • All sectors of the food chain should Implement Good
Hygienic Practices (GHP) and Good Manufacturing
Practices (GMP) as well as implement a food safety
management system based on the principles of Hazard
Analysis Critical Control Points (HACCP).
• Food manufacturers should also test against
microbiological criteria, as appropriate, when validating
and verifying the correct functioning of their HACCP
based procedures and other hygiene control measures.

22. • In addition, producers manufacturing food associated
with risks of Listeria must conduct environmental
monitoring to identify and eliminate niche
environments, including areas that favour the
establishment and proliferation of L. monocytogenes.
• Modern technologies using genetic fingerprint - Whole
Genome Sequencing (WGS) - allow for more rapid
identification of the food source of listeriosis outbreaks
by linking L. monocytogens isolated from patients with
those isolated from foods.

23. D E T E C T I O N O F F O O D B O R N
PAT H O G E N S
P R I N C I PA L S T H AT G U I D E T H E D E V E L O P M E N T O F F O O D T E S T I N G
S T R AT E G I E S
M O L E C U L A R T E C H N I Q U E S T O E N S U R E F O O D S A F E T Y.
P U L S E N E T P R O G R A M E

25. M O L E C U L A R
T E C H N I Q U E S
• PCR combined with
restriction fragment length
polymorphism(RFLP).
• Pathogen-specific PCR
primer.
• Microarray technology.

26. P U L S E N E T
P R O G R A M
• This program is for the
early detection of food-
born illness, particularly
during an outbreak.
• The basis of the program
is the use of pulse-field gel
electrophoresis(PFGE).

27. • L . M O N O C Y T O G E N E S I N F O O D A R E K I L L E D B Y
PA S T E U R I S AT I O N A N D C O O K I N G .
• P R A C T I C I N G S A F E F O O D H A N D L I N G .
Prevention

28. • Following the WHO Five Keys to Safer Food
1.Keep clean.
2.Separate raw and cooked.
3.Cook thoroughly.
4.Keep food at safe temperatures.
5.Use safe water and raw materials.

31. • Persons in high risk groups should:
A. Avoid consuming dairy products made of
unpasteurised milk; deli meats and ready-to-eat meat
products such as sausages, hams, patés and meat
spreads, as well as cold-smoked seafood (such as
smoked salmon)
B. Read and carefully follow the shelf life period and
storage temperatures indicated on the product label.
• It is important to respect the shelf-life and storage temperature written
on labels of ready-to-eat foods to ensure that bacteria potentially
present in these foods does not multiply to dangerously high numbers.
• Cooking before eating is another very effective way to kill the bacteria.

32. • Fully cooking meats
• Washing fresh vegetables
• Carefully cleaning utensils
• Avoiding pasteurised dairy products

33. – H T T P S : / / W W W. W H O . I N T / N E W S - R O O M / FA C T- S H E E T S /
D E TA I L / L I S T E R I O S I S
H T T P S : / / W W W. N C B I . N L M . N I H . G O V / P M C / A R T I C L E S /
P M C 3 7 2 8 3 1 /
H T T P S : / / E F S A . O N L I N E L I B R A RY. W I L E Y. C O M / D O I / F U L L /
1 0 . 2 9 0 3 / J . E F S A . 2 0 1 8 . 5 1 3 4
B O O K S : P R E S C O T T ’ S M I C R O B I O L O G Y 1 0 T H E D I T I O N
H A R R I S O N I N T E R N A L M E D I C I N E 2 0 T H E D I T I O N
Bibliography