GROUP 17 SEMESTER 6 (14/15) Supervisor : Dr. Samah Sabri PBL members : Ola Abdul Hamid Arif Ehsan Harith…

GROUP 17SEMESTER 6 (14/15)

Supervisor : Dr. Samah SabriPBL members :

OlaAbdul Hamid

ArifEhsanHarith

Nasuha Diana

SharifahAinaFarah

Objectives:

• Understand the definition of food poisoning• The risk factors, causes and pathogenesis of food

poisoning• The clinical manifestations of food poisoning• How to manage patients with food poisoning• Methods to prevent and control food poisoning

cases

DEFINITION

• It is an illness acquired by consumption of food or drinks contaminated with either living bacteria or their toxin or inorganic substance and poison

• Characterized by history of ingestion of contaminated food and short incubation period

Types of food poisoning

• Most frequently , food poisoning may be due to infection caused by bacteria, viruses, parasites and infrequently prions. More than 200 infictious causes exist.

• Sometimes it’s not the bacteria that cause the problem, but the toxin that bacteria produce in the food. This is the case with Staphylococcal food poisoning and with botulism. (Intoxication)

• Other illnesses may involve chemical toxins produced in certain foods that are poorly cooked or stored.

RISK FACTORS• Eating raw or undercooked meat or poultry, unpasteurized

dairy products, raw shellfish, unwashed fruits and unwashed vegetables.

• Food poisoning is more comman at picnics and buffets , where food is often left out of the refrigerator for a long time.

• People who are at a high risk include:

Those having a chronic medical condition Pregnant women Those having a weakend immune system, which could be caused by

drugs taken after an organ transplant, certain chemotherapy medicines or infection with HIV.

Causative agent of food

poisoning

Viral Bacteria Parasite

•Hepatitis A & E

SalmonellaCampylobacterE.ColiShigellaVibrio Parahaemolyticus

•Giardia Lamblia•Trichinella Spiralis

Causative Agent of

Intoxification

Bacillus cereus(vomiting toxin) Clostridium botulinum Staphylococcus aureus

•I.P : 12-36 hours•Primarily neuromuscular paralysis•Badly preserved vegetables,meat and fish

•I.p : 1-6 hours•Primarily vomiting & diarhea •Rice,meat & vegetable

•I.P : 2-4 hours•Primarily vomiting•Meat, ccustard & salad

1)Staphylococcus AureusImportant features :

• Gram-positive cocci• Singles or pairs .Short chains,

tetrads & irregular• Golden yellow colony on agar• Non motile• Non spore• Facultative anaerobe

Pathogenesis

• S.Aureus produce enterotoxin while multiplying in food

• Produce 6 serogically different types of enterotoxins ( A,B,C,C2,D and E)

• Mostly caused by entertoxin A

• Isolates commonly belong to phage type iii. These enterotoxins tend to be heat

stable

• Low temperature heat inactivated enterotoxin can undergo reactivation in some

food

• Ingestion of enterotoxin can induce diarrhea & vomiting.

• Staphylococcal enterotoxins act superantogens, binding to MHCii molecules & stimulating T cells to divide & produce lymhokines such as IL-2 &Tnf alpha,which induces diarrhea.

• The toxin acts on the receptor in the gut & sensory stimulus are carried to the vomittung center in the brain by vagus & sympathetic nerves

• Incubation Period : 1-6 hours

• Clinical Features :Onset is suddenCharacterized by : diarrhea ,vomitting with no feverThe illness last less than 12 hours

Labaratory Diagnosis :Dilutations of food may be plated on Baird-Parker agar or Mannitol Salt

agarEnterotoxin may be detected & identified by gel diffusion

2) Bacillus Cereus• A gram positive aerobic spore bearing bacilli• Its found abundantly in environment & vegetation

Pathogenesis

• During the slow cooling, spores germinate & vegetative bacteria multiply, then they sporulate again.

• Sporulation is also associated with toxin production. The toxin is heat-stable & can be easily withstand the brief high temperatures

• the short-incubation form is cauused by a preformed heat-stable enterotoxin of molecular weight loss than 5k daltons

• Long-incubation food poisoning is frequently associated with meat or vegetable-containing foods after cooking

• The long-incubation form of illlness is madiated by a heat-labile enterotoxin (molecular weight of approximately 50k daltons), which activates intestinal adenylate cyclase and causes intestinal fluid secretion

• Incubation Period :Short incubation : 1-6 hoursLong incubation : 8-16 hours

• Clinical Features :Characterized by : nausea, vomiting & abdominal crampsWithin 16 hours of eating contaminated food, patients suffer about of vomiting

that generally last for less than a dayDiarrhea may be small volume & watery

• Laboratory Diagnosis :Short incubation: isolation of B.aureus from the incriminated foodLong incubation : by isolation of the organism from stool & food

3) Clostridium Botulinum• Its a gram positive anaerobic spore

bearing bacilli• Widely distributed in soil,

sediments of lakes & ponds & decaying vegetation

Pathogenesis• Not all strains of C.Botilinum produce the botulinum toxin

• 7 toxigenic types of the organism exist, each producing an immunologically distinct form of botulinum toxin designated as A,B,C1,D,E,F & G.

• Lysogenic phages encode toxin C & D serotypes.

• Food-borne botulism is not an infection but intoxification since it results from the ingestion of foods that contain the preformed clostridial toxin.

• If contaminated food insufficiently sterilized, the spores may germinate & produce botulinum toxin

• The toxin is released only after the death & lysis of cells

• The toxin resists digestion & absorbed by the upper part of the GUT and then into the blood

• It then reaches the peripheral neuromuscular synapses where the toxin binds to the presynaptic stimulatory terminals & blocks the release of the neurotransmitter acetylcholine

• This results in flaccid paralysis.

• Even 1-2 microgram toxin can be lethal to humans

• Incubation:12-36 hours

• Clinical Features :Vomiting,thirst,dryness of mouth,constipation,ocular paresis (blurred

vision), difficulity in speaking, breathing & swallowing

• Laboratory Diagnosis :Food is homogenized in broth & inoculated in Robertson cooked meat

medium & blood agar or egg-yolk agar, which is incubated anaerobically for 3-5 days at 37'C.

The toxin can be demonstrated by injecting intraperitoneally the extract of food or culture into mice or guinea pig

CLINICAL MANIFESTATION

Generally, food poisoning causes some combination of :

NauseaVomiting Watery diarrheaAbdominal pain and crampsFever

After eating tained food, abdominal cramps, diarrhea & vomiting can start :

Staph infection : as early as one hourCampylobacter : as late as 10 days may take even longer in the case of parasite infections such as Giardia

Lamblia

Symptomps can last from one day up to a couple of months or longer, depending on the type of infection

Symptoms of chemical or toxin food poisoning such as that from poisonous mushrooms :vomitingdiarrheasweatingdizzinesstearing in the eyesexcessive salivationmental confusionstomach pain

MANAGEMENT

Control nausea and vomitingDont eat fried, greasy and sweet foodAvoid solid foods until vomiting ends. Then eat light, blands foods

such as saltine crackers or breadsPrevent dehydration

Drink clear fluids, starting with small sips and gradually drinking more.

When to call a doctorIf accompanied by a fever, with blood or dark stoolsIf diarrhea lasts more than 3 days

PREVENTIONS• Wash hands thoroughly before handling food • Keep food preparation surfaces and utensils clean & disinfected • Prepare & store raw meat & "ready to eat" food separately• Use the food before the expiry date• Keeps the pets away from food & food preparation surfaces• Defrost food, particularly meat & poultry thoroughly before cook• Cook food thoroghly

CONTROLWhat do you have to if you have symtomps of food borne illness :

Visit your doctor as soon as possibleCooperate with the doctor by giving the needed samples

If a member of your family are suffering from the symtomps of food poisoning :

Wash your hands after contact with the sick personDo not use the same towel or face cloth as someone who is suffering

with food borne illnessDisinfect door, toilet handles, taps & the toilet seat after use Disinfect the toilet bol frequentyDrink plenty of fluids while you are ill to prevent dehydration

SummeryOrganism Pathogenesis I.P

(hr.)C/P Food Type Treatment Prognosis

Salmonella Infective 12-48 Bloody diarrhea , abdominal Pain

and fever

Infected meat or egg

Antibiotics Good

S. aureus Toxigenic 1-6 Vomiting and slight diarrhea

Milk and its products and

pastries

Fluid therapy Self- limited

C.perfrengens InfectiveEnterotoxigenic

12-24 Moderate diarrhea and colicky pain

Reheated meat dishes

Antibiotics Good

C. jejuni InfectiveEnterotoxigenic

16-48 Vomiting ,bloody diarrhea, abd. Pain and fever

Contaminated food and drinks

Antibiotics Good

V.parahaemolytic

us

Infective

Enterotoxigenic

6-36 Vomiting, diarrhea and

abdominal pain

Sea food Antibiotics Good

C. botullinium Toxigenic 12-72 Respiratory, neurogenic

Canned food Antitoxin Fatal

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