CLINICAL TOXICOLOGY 1- FOODBORNE DISEASES BACTERIAL FOODBORNE DISEASES PARASITE (TOXOPLASMOSIS) 2-...

CLINICAL TOXICOLOGY

1- FOODBORNE DISEASES

• BACTERIAL FOODBORNE DISEASES

• PARASITE (TOXOPLASMOSIS)

2- FOOD ADDITIVES• PRESERVATIVES

• COLORING AGENTS

BACTERIAL FOODBORNE DISEASES

A- Bacteria are by far the most common contaminants with food and cause many different foodborne diseases

• Most diarrhea (1/2 to 1/3) caused by foodborne bacteria

• Symptoms of foodborne diseases can range from mild to severe

• Some people asymptomatic but can transmit the disease

B- Definition of foodborne disease

Eating food that contains a sufficient quantity of either pathogenic microorganism or their toxins to cause symptoms

BACTERIAL FOODBORNE DISEASES- Therefore, the presence of bacteria is not important but

the number of bacteria ingested.- The dose required to cause illness can vary markedly

for different microorganism

For examples:• Salmonella requires 100,000 bacterial cells inorder to

produce symptoms

• Shigella requires 10 bacterial cells in order to produce illness

• Staphyllococcus required 500,000 microorganisms in order to produce illness

PATHWAYS OF FOODBORNE INFECTION CAUSED BY MICROORGANISM

1-Ingested pathogenic microorganism then *The microrganism penetrates the intestinal mucosa

and colonize the GIT - Examples: Shigella, Salmonella, Escherichia coli

2 –Microorganism travels from GIT to other tissues Then it stay in this tissues for examples: - Hepatitis A virus goes to the liver - Trichinella spiralis goes to muscle

3- The toxins are released as the infecting microorganism multiplies or lyses in the intestinal tract

Examples Vibro cholerae, Clostridium perfringens and E. coli

THE MOST COMMON FOODBORNE MICROORGANISMS

A- BACTERIAL

1-Salmonellae species

* Salmonellae Typhi

* S. enteritidis

* S. choleraesuis

2- Pathogenic E. coli

3- Clostridium perfringens types A & C

4- Clostridium botuli


5- Staphyllococcus aureus

6- Shigella species

* Shigella dysentry flexneri bovidii sonnei

7- many other bacterias

B- PARASITES1- Toxoplasmosis gondii

2- Trichinella spiralis

3- other parasites such as

- tapeworms

- roundworms

- fish tapeworms


C- Viruses

1- Hepatitis

2- Human rotavirus

3- Norwalk-type viruses

SALMONELLAE SPECIES

• Salmonellae species are gram negative bacilli belongs to family enterbacteriacea

• Salmonellae has three species - Salmonellae typhi - Salmonella enteritidis - Salmonellae choleraesuis

• The main reservoir for Salmonellae is - intestinal tract of animals - poultry products such as eggs - meat

CHARACTERISTICS OF SALMONELLAE

• Salmonellae grows in aerobic & anaerobic conditions

Salmonellae is sensitive to lower PH that explains it requires large number of bacterial cells to induce symptoms

• Most strains are heat sensitive but some are heat resistant

• Drying or freezing does not kill it

• Contaminated food looks & smell normal

SOURCES OF SALMONELLAE

• Most common sources of salmonellae are EGGS & poultry products

• Ice cream made from processed eggs and home made ice cream made with raw eggs

• Deli salads, cold roasted meat

• Infected food handler also source of salmonellae especially workers in restaurants

SOURCES OF SALMONELLAE

• Utensils such as cutting boards and cutting utensils used for uncooked meat and poultry may serve to inoculate other foods

• Raw milk and its product such as chedder cheese made from raw milk

• Contaminated water

• Pets especially reptile

SYMPTOMS OF SALMONELLOSIS• Usually occur 12-24 hours after eating and

subside in 24-48 hours• SYMPTOMS - Diarrhea resolve within 1-5 days - Cramps - Nausea and vomiting - Chills and fever which resolve within two

weeks in Typhi species) - Stool may contains mucous or blood

SYMPTOMS OF SALMONELLOSIS• SYMPTOMS - in severe case: bacteria travel to distant tissues - causing * meningitis * pneumonia - Typhoid fever symptoms similar to influenza and causes constipation while Salmonellae

enteriditis caused diarrhae

TREATMENT OF SALMONELLA1- Enterocolitis uncomplicated * not requires therapeutic intervention2- Enterocolitis complicated A- Adult: * Ciprofloxacin 500 mg po for 3-7 days * Norfloxacin 400 mg q12 hours for 3-7 days * Azithromycin 1g once, then 500 mg qd for 6 days

B- Children * Ampicillin 50-100 mg/kg/24hrs in 4 divided doses for 10-14

days * or Trimethoprim-sulfamethoxazole 10mg-50mg/kg/24 hrs in

divided doses for 10-14 days

TREATMENT OF SALMONELLA

3- Bacteremia or Localized infections A- Adult:

* Ciprofloxacin 400 mg i.v. bid or 500 mg po for 14 days or * Ceftriaxone 1-2 g i.v./i.m. qd for 14 days

B- Children

* Ampicillin 200 mg/kg/24hrs in 4 divided doses for 10-14 days

* or Trimethoprim-sulfamethoxazole 10mg-50mg/kg/24 hrs in divided doses for 10-14 days


4- Chronic carrier

* Ampicillin 2-4 g/day plus probenecid 1-2 g/day both divided into 4 oral doses for 6 weeks

* or Trimethoprim(40-160mg)-sulfamethoxazole (200-800mg)/day divided in 2 doses for 6 weeks

* If gallstones present give Ciprofloxacin 500 mg po for 4-6 weeks or *Norfloxacin 400 mg bid for 4 weeks


Anti-diarrhae is contraindicated because:

* it prolongs the illness

* it precipitates perforation of intestine

Escherichia coli1- Characteristics of E. coli

* It is gram negative bacillus belonging to the family Enterobacteriacea

* It is marker for non-sanitary handling of food and equipment

* Most strains are halmless and live in the intestine of healthy human and animal

2- SOURCES OF E. coli

• GIT of animals

• Human feces

• Dairy product such as cheese

• Raw ground meat or under cooked meat

• Cutting boards and contaminated equipment

Escherichia coli1- Characteristics of E. coli O157:H7 * E. coli O157:H7 produces powerful toxins leads to

bloody diarrhea

* It can induce hemolytic uremic syndrome leading to acute renal failure

* Antibiotic has no value

* Anti-diarrhea such as lopramide should be avoided

3- Long term complication of E. coli O157:H7

* one-third of patient develop HUS

* They require dialysis

* develop high blood pressure

* develop seizure & blindness

* paralysis

* part of the bowel removed

Escherichia coli

3- PREVENTION E. coli O157:H7

* Cook all meat well DONE at least reach temperature 160 F

* Use pasteurized milk or any juices

* good hygiene

SYMPTOMS OF E. COLI1- Most cases mild fluid loss

2- Most Enteropathogenic strains ( ETEC) diarrhea

* Resolves within 24-48 hours without comlications

* But some cases last for 7 days in adult and longer duration in children

3- Vomiting is rarely occur

SYMPTOMS OF E. COLI4- Enteropathogenic strains cause

* Sudden onset of severe diarrhea

* with or without abdominal cramping

* followed by the development of watery diarrhea

* then bloody diarrhea

SYMPTOMS OF E. COLI

2- Enteropathogenic strains produce toxins causes:

* severe diarrhea

* with profound dehydration & shock

* Without fever

5- Enteroinvasive strains penetrate the epithelium and cause:

* fever & chills & headache

* Abdominal cramp

* profuse watery diarrhea

SYMPTOMS OF E. COLI


* severe diarrhea


* Without fever

6- Colohaemorrhagic strains * cause changes in the colon similar to colitis

* Verocytotoxin is responsible for frank bloody diarrhea

* and severe Abdominal cramp

* in severe cases indistinguishable from cholera

TREATMENT OF E. COLI


* severe diarrhea


* Without fever

1- Most ETEC resolves within 24-48 hours without complication

* not require specific treatment

* Some cases require oral electrolytes replacement therapy (ORT) * Because no vomiting

* Antibiotic seldom require



* severe diarrhea


* Without fever

2- Antibiotics * Sulfamethoxazole double stregth

(bactrim or septrin Forte) bid for 3 days

OR

* Ciprofloxacin 500 mg bid for 7 days

*Bismuth subsalicylate (Pepto-Bismol) may

have anti-inflammatory & bactericidal activity



* severe diarrhea


* Without fever

• In case of E. coli O157:H7 antibiotic may precipitate kidney complication

• Anti-diarrhea such as loperamide (Imodium) SHOULD BE ALSO AVOIDED

SHIGELLOSIS (Bacillary dysentry)


* severe diarrhea


* Without fever

1- Characteristics

• It is self limited to intestinal infection

• Incubation period from 1-7 days (average 4 days)

• It invades colons and end of ileum

• It causes extensive inflammatory changes



* severe diarrhea


* Without fever

* Four species are caused this disease as follows:

- Dysentriae type-1 This is responsiblefor most severe type

- Flexneri

- bovidii

- sonnei



* severe diarrhea


* Without fever

2- SOURCES

* Poor personal hygiene

* poor sanitation

* Majority of caused by fecal-oral transmission

* food served by worker infected with shigellosis



* severe diarrhea


* Without fever

3- SYMPTOMS

* Malause

* Fever especially in children rises to 40-41 C

* Hyperactive bowel sound

* Abdominal tenderness



* severe diarrhea


* Without fever

* frequent (multiple 10-25 per day) small volume watery diarrhea

* followed by dysentry (blood stool) within few days

* painful straining often leads to rectal prolapsed



* severe diarrhea


* Without fever

*Small volume stool which greenish in color

* Often contains mucous and /or blood

* Severe case of shigellosis can progress to toxic dilation and colon perforation

* this perforation may lead death



* severe diarrhea


* Without fever

* Hemolytic uremic syndrome (HUS)

* HUS is a result of Shigatoxins causes

* Endothelial damage of lamina propria

* Resulting in microangiopathic changes

* renal failure as result of HUS



* severe diarrhea


* Without fever

* flexneri infection can progress to Reiter’s syndrome

* Which can last for months or years

* Can leads to chronic arthritis manifested:

- Painful joint

- irritated eyes

- Painful urination

TREATMENT SHIGELLOSIS


* severe diarrhea


* Without fever

* Rarely requires electrolytes and fliud replacement therapy

* Anti-peristalsis is contraindicated

* which worsening the course of shigella

* it prolongs fever , dysentry and possibly resulting to Toxic megacolon



* severe diarrhea


* Without fever

• ANTIBIOTIC IS IMPORTANT IN THE TREATMENT

• Ciprofloxacin is highly effective

• But not recommended under 17 years old

• because of cartilage toxicity



* severe diarrhea


* Without fever

• Avoid ampicillin

• may precipitate HUS & renal failure

• Resistant developed also against

• Co-trimoxazole

• & nalidixic acid



* severe diarrhea


* Without fever

• Administered glucose

• to reverse hypoglycemia

• Patient requires prolong protein supplement

• because the illness causes protein loss

SUMMARY OF TRAVELLERS DIARRHEA

1- MOST COMMON CAUSES

A- Enterotoxogenic E. coli

* Self limited illness lasting for several days

2- LESS COMMON

* Shegilla , Entamoeba histolytica

, Campylobacter, vireses

TRAVELLERS DIARRHEA

Stage of symptoms

A- Acute watery diarrhea * Entertoxigenic E. coli accounts for the majority ( 40%)of these episodes

and last about 4-7 days * In severe case requires hospitalization

B- Dysentry ( diarrhea with blood) * mostly caused by - Shegilla - E. coli O157:H7 - Entamoeba histolytica – Campylobacter

C- Persistentent diarrhea with or without intestinal malabsorption

PROPHYLAXIS AGAINST TRAVELLERS DIARRHEA

1- Generally do not prescribe drugs prophylactically

2- but instruct the person to begin treatment when symptoms appear

3- However , Ciprofloxacin 500 mg once daily or levofloxacin 400 mg once daily is recommended for adult only

4- Bismuth subsalicylate (pepto-Bismol) is less effective

TREATMENT TRAVELLERS DIARRHEA

1- Antidiarrhea such as loperamide (Imodium) & other anti-diarrhea

2- Plus single dose of ciprofloxacin (750 mg) or

-Levofloxacin 500 mg or ofloxacin 400 mg

- usually symptoms relief in less than 24 hours

TREATMENT TRAVELLERS DIARRHEA

3- If diarrhea is severe or

associated with high fever or bloody stools:

- ciprofloxacin 500 mg BID for three days in adult

- Trimethoprim-sulfamethoxazole ( resistant has been developed in many areas)

4- ORT (oral rehydratio replacement therapy)

CLOSTRIDIUM PERFRINGENS

TYPES:

* Type A: It’s symptoms is mild form

* Type C: Severe type It called enteritis necrotican

* Which causes necrotizing enteritis intestinal (small intestine) ulceration

* which leads to perforation in 40%

* and death

CLOSTRIDIUM PERFRINGENS Type A

1- CHARACTERISTICS OF TYPE A:

* Induced by ingested cooked meat or poultry that has not been consumed within 2-3 hours

* Spore multiply rapidly and produce a heat labile enterotoxin

* Incubation period 6-12 hours which is important diagnostic clue

*It is Spore forming and the spore stands at high temperature 100 C


• The spore is highly heat resistant and may survive cooking procedure

• When spore ingested, it replicates in small intestine and produces its toxin

2- SOURCE:• Meat and its products are good media to grow• It is common from food serve in institution• Condition of low oxygen favour the growth of this bacteria such

roast meat hold for long time before cooking• Eating cold meat increases chance of infection with this bacteria


3- PREVENTION

• Rapidly refrigerate the meat

• Cure meat

• Avoid the habit of cooling the food at room temperature the freeze.

• Food must enter freezer immediately


4- SYMPTOMS• The symptoms are mild

• Occur often within 8-24 hours of ingestion contaminated food and usually last for one day

• Abdominal pain (81%) and watery diarrhea (92%) are common

• Fever (24%) and vomiting (9%) are uncommon


5- TREATMENT• Symptomatic therapy to alleviate cramping

causing abdominal pain such as antispasmotic

• The illness is self limited and rarely last more than 24 hours

• Fluid therapy if there is evidence of electrolytes loss

• No value of antibiotic

CLOSTRIDIUM PERFRINGENS Type C

1- CHARACTERISTICS

• It produces toxins called enteritis necroticans which causes necrotizing enteritis

• It causes also intestinal (small intestine) ulceration

• Which leads to perforation in 40% of patients

• It can lead to death

CLOSTRIDIUM PERFRINGENS Type C

2- TREATMENT

• Anti-toxin against beta toxin of Clostridium perfringens type C

Staphyllococcus aureus

1- CHARACTERISTICS

CLINICAL TOXICOLOGY 1- FOODBORNE DISEASES BACTERIAL FOODBORNE DISEASES PARASITE (TOXOPLASMOSIS) 2-...

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