Transcript PHL462-TOXICOLOGY

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
THE MOST COMMON FOODBORNE MICROORGANISMS
5- Staphyllococcus aureus
6- Shigella species
* Shigella dysentry
7- many other bacterias
B- PARASITES
1- Toxoplasmosis gondii
2- Trichinella spiralis
3- other parasites such as
- tapeworms
- roundworms
- fish tapeworms
flexneri
bovidii
sonnei
THE MOST COMMON FOODBORNE MICROORGANISMS
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 SALMONELLA
1- Enterocolitis uncomplicated
* not requires therapeutic intervention
2- 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 1014 days
* or Trimethoprim-sulfamethoxazole 10mg-50mg/kg/24
hrs in divided doses for 10-14 days
TREATMENT OF SALMONELLA
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 (200800mg)/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
TREATMENT OF SALMONELLA
Anti-diarrhae is contraindicated because:
* it prolongs the illness
* it precipitates perforation of intestine
Escherichia coli
1- 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 coli
1- 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. COLI
1- 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. COLI
4- 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
5- Enteroinvasive
2Enteropathogenic
strains
strains produce
toxins causes:
penetrate
the epithelium and cause:
* fever
severe&diarrhea
chills & headache
* with profound dehydration & shock
* Abdominal cramp
* Without fever
* profuse watery diarrhea
SYMPTOMS OF E. COLI
6- Colohaemorrhagic
2Enteropathogenic strains
strainsproduce
causes:in the colon similar to colitis
*toxins
cause changes
*
severe diarrheais responsible for frank
* Verocytotoxin
bloody
diarrhea dehydration & shock
* with profound
*
and severe
Abdominal cramp
* Without
fever
* in severe cases indistinguishable from
cholera
TREATMENT OF E. COLI
1ETEC resolves within
24-48
hours
2- Most
Enteropathogenic
strains
produce
without
complication
toxins causes:
** not
require
specific treatment
severe
diarrhea
with profound
dehydration
& shock
** Some
cases require
oral electrolytes
replacement
therapy (ORT) * Because no vomiting
* Without fever
* Antibiotic seldom require
TREATMENT OF E. COLI
2Enteropathogenic
strains
produce
2- Antibiotics
toxins
causes:
* Sulfamethoxazole double stregth
* severe
diarrhea
(bactrim
or septrin Forte) bid for 3 days
* withOR
profound dehydration & shock
* Ciprofloxacin 500 mg bid for 7 days
* Without fever
*Bismuth subsalicylate (Pepto-Bismol) may
have anti-inflammatory & bactericidal activity
TREATMENT OF E. COLI
2- Enteropathogenic strains produce
• In case of E. coli O157:H7 antibiotic may
toxins
causes:
precipitate kidney complication
* severe diarrhea
• Anti-diarrhea
such
as loperamide
(Imodium)
* with profound
dehydration
& shock
SHOULD BE ALSO AVOIDED
* Without fever
SHIGELLOSIS (Bacillary dysentry)
1- Characteristics
2Enteropathogenic strains produce
toxins causes:
• It is self limited to intestinal infection
* severe diarrhea
• Incubation period from 1-7 days (average 4 days)
* with profound dehydration & shock
* Without
feverand end of ileum
• It
invades colons
• It causes extensive inflammatory changes
SHIGELLOSIS (Bacillary dysentry)
2- Enteropathogenic strains produce
* Four species are caused this disease as follows:
toxins causes:
Dysentriae
type-1
* severe diarrhea
This is responsiblefor most severe type
* with profound dehydration & shock
- Flexneri
* Without fever
- bovidii
- sonnei
SHIGELLOSIS (Bacillary dysentry)
2Enteropathogenic
strains
produce
2- SOURCES
toxins causes:
* Poor personal hygiene
* severe diarrhea
* poor sanitation
* with profound dehydration & shock
caused by fecal-oral transmission
** Majority
Withoutoffever
* food served by worker infected with shigellosis
SHIGELLOSIS (Bacillary dysentry)
2Enteropathogenic
strains
produce
3- SYMPTOMS
toxins causes:
* Malause
* severe diarrhea
* Fever especially in children rises to 40-41 C
* with profound dehydration & shock
Without fever
** Hyperactive
bowel sound
* Abdominal tenderness
SHIGELLOSIS (Bacillary dysentry)
2- Enteropathogenic strains produce
* frequent (multiple 10-25 per day) small
toxins
causes:
volume watery diarrhea
* severe diarrhea
followed
by dysentry
(blood&stool)
within
** with
profound
dehydration
shock
few days
* Without fever
* painful straining often leads to rectal
prolapsed
SHIGELLOSIS (Bacillary dysentry)
2- Enteropathogenic strains produce
*Small volume stool which greenish in
toxins
causes:
color
* severe diarrhea
* Often contains mucous and /or blood
* with profound dehydration & shock
* Severe case of shigellosis can progress to
* Without
fever
toxic
dilation
and colon perforation
* this perforation may lead death
SHIGELLOSIS (Bacillary dysentry)
2-*Enteropathogenic
strains
produce
Hemolytic uremic syndrome (HUS)
toxins causes:
* HUS is a result of Shigatoxins causes
* severe diarrhea
* with
profound
dehydration
& shock
Endothelial
damage
of lamina
propria
*
Without
fever
* Resulting in microangiopathic changes
* renal failure as result of HUS
SHIGELLOSIS (Bacillary dysentry)
2-*Enteropathogenic
strains
produce
flexneri infection can progress to Reiter’s
toxins
causes:
syndrome
* severe diarrhea
* Which can last for months or years
*
profound
dehydration
& manifested:
shock
* with
Can leads
to chronic
arthritis
Painful
joint
* Without fever
- irritated eyes
- Painful urination
TREATMENT SHIGELLOSIS
2-*Enteropathogenic
strains
produce
Rarely requires electrolytes and fliud
toxins
causes:
replacement
therapy
* severe diarrhea
* Anti-peristalsis is contraindicated
* with profound dehydration & shock
* which worsening the course of shigella
* Without fever
* it prolongs fever , dysentry and possibly
resulting to Toxic megacolon
TREATMENT SHIGELLOSIS
2Enteropathogenic
strains
produce
• ANTIBIOTIC IS IMPORTANT IN THE
toxins
causes:
TREATMENT
* severe diarrhea
• Ciprofloxacin is highly effective
* with profound dehydration & shock
* Without
fever
• But
not recommended
under 17 years old
• because of cartilage toxicity
TREATMENT SHIGELLOSIS
2- Enteropathogenic strains produce
• Avoid ampicillin
toxins causes:
* severe
diarrhea
• may
precipitate
HUS & renal failure
* with profound dehydration & shock
• Resistant developed also against
* Without fever
• Co-trimoxazole
• & nalidixic acid
TREATMENT SHIGELLOSIS
2- Enteropathogenic strains produce
• Administered glucose
toxins causes:
*
severe
diarrhea
• to reverse hypoglycemia
* with profound dehydration & shock
• Patient requires prolong protein supplement
* Without fever
• 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
CLOSTRIDIUM PERFRINGENS
Type A
• 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
CLOSTRIDIUM PERFRINGENS
Type A
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
CLOSTRIDIUM PERFRINGENS
Type A
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
CLOSTRIDIUM PERFRINGENS
Type A
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