Download Spore forming bacteria

Spore forming bacteria
Spore forming bacteria
!Spore former
!Bacillus
!Clostridium
!Desulfotomaculans
!Gram negative
!Converse sulfate to sulfide
!Sporolactobacillus
!Rod shape, microaerophilic bacteria
!Sporpsarcina
!Cocci, aerobic bacteria
Importance of spore former
in food
!Response to temperatures
!Endospore formation
!Resistance
!Morphology
!cortex --peptidoglycan
!germ cell wall
!nuclear mass
!Sporulation
!Germination
Spore cycle
!Control of spore forming bacteria
! Prevent sporulation
!Condition that bacteria can grow: no sporulation
! Prevent activation
!Dormant spore: no hazard
! Prevent initiation
!Prevent germinate spore to grow
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Bacillus cereus
Food poisoning
Bacillus cereus
! Gram positive
! Motile
! Spore forming bacteria
! Facultative aerobic bacteria
! Grows within the temperature range of 10-48 C
! optimum temperature 28-35 C
! Endospores are formed freely, in almost every cells,
under conditions favorable for growth
! Two forms of food poisoning
! Diarrhea syndrome and emetic syndrome
Bacillus cereus
! Unique characteristic
! Temperature 10 to 48 C
! Produce toxins
!Diarrhea toxin: Diarrhea syndrome (toxin formed in intestine)
! Heat-labile enterotoxin
! Large MW
!Emetic toxin: Emetic (Food intoxication)
! Heat stable toxin (121 C for 90 min)
! Low MW
! Not destroy by refrigeration and cooking
! Infective dose: high infective dose (>105 CFU/g)
Bacillus cereus food poisoning
! Foodborne intoxication
! Incubation period: 1-5 hrs (8-16 hrs:Diarrhea syndrome)
! Duration of illness: 6-24 hrs
! Clinical signs
! Diarrhea type
!Watery diarrhea
!Abdominal cramps
!Nausea but vomiting rarely occurs
!Symptoms persist for 24 hrs
! Emetic type
!Sudden onset of vomiting
!Abdominal cramps
!Some patients may develop diarrhea
! Usually self limiting and not severe
Bacillus cereus outbreaks
! Most common: Rice or cereal product
! High carbohydrate food
! Starchy
! Wide variety of foods including meats, milk,
vegetables and fish have been associated with
diarrheal type
! All ages are susceptible to B. cereus food poisoning
! Symptoms similar to Staphyloccus food poisoning
(emetic type) and C. perfingens food poisoning
(diarrheal type)
Bacillus cereus outbreak
! Emetic syndrome
! Associated with Chinese restaurant
! Fried rice
! The practices flavor to food poisoning
!The preparation of large amount of cooked rice (some B.
cereus can survive)
!Holding the cooked rice at warm temperature for long periods
(B. cereus spores can germinate and the vegetative cells
multiply and form enterotoxin)
!The toxin can survive the stir-fry temperature
Bacillus cereus case study
! B. cereus food poisoning account for only 2% of
outbreaks
! B. cereus food poisoning associated with Fried rice
! 2 daycare centers:
!Acute gastroenteritis
!Following lunch
!Lunch served to 82 children, 9 adults
!Nausea, vomit, abdominal cramps and diarrhea
!Median incubation period: 2 hrs
!Symptom resolved: 4 hrs after onset
Bacillus cereus case study
! Interview cases
!Chicken fried rice
!Prepare at a local restaurant
!29% of persons who ate fried rice compare to 0% who
did not eat
!Leftover chicken fried rice
!B. cereus > 106 CFU/gm
! Source of contamination?
! Rice had been cooked at night
! Cooled at room temperature before refrigeration
! In the morning rice was pan-fried and delivery to the day
care
! Foods was served at noon
Bacillus cereus
!Bacillus cereus prevention and control
!Education
!Control cooking temperature, storage temperature
!Proper temperature
!< 5 C or > 60 C
!Reheating before serving
!Limit condition for B. cereus
!pH < 5
!Temperature < 5
!Water activity < 0.95
Isolation of Bacillus cereus
! Suspected food, vomitus and feces of patients
! Selective media for B. cereus
! Polymyxin B: Inhibit Gram negative bacteria
! Egg yolk: Bacteria produce lecithinase
! Manitol: B. cereus fermented manitol
! pH indicator-bromthymol blue
! Colony: Distinctive blue color surrounded by precipitation of
egg yolk blue zone
! Serology typing for B. cereus enterotoxin is
developed
! Vomiting type toxin can be detected by animal
models
Botulisum
Clostridium botulinum
! Gram positive
! Rod shape
! Spore forming bacteria
! Anaerobic bacteria
! The spores are heat resistant and can survive in
foods
! Seven types (A, B, C, D, E, F and G) of botulisum are
recognized
! based on the antigenic specificity of the toxin
! Types A, B, E and F: human botulism
! Types C and D: botulism in animals (Horse, cattle, poultry)
Clostridium botulinum
! Foodborne botulism (Foodborne intoxication)
! Distinct from wound botulism and infant botulism
! Severe type of food poisoning
! Ingestion of foods containing the potent neurotoxin
! Neurotoxin
! Heat labile and can be destroyed if heated at 80oC for 10
minutes or longer.
! The incidence of the disease is low,
! Considerable concern because of its high mortality rate
Clostridium botulinum
! Unique characteristic
! Strict anaerobic bacteria
! Heat labile toxin
! Produce neurotoxin
! Infective dose: Low infective dose
! A very small amount (a few nanograms) of toxin can cause
illness
Botulisum
! Foodborne intoxication
! Incubation period: 12-19 hrs (Usually 18-36 hrs)
! Duration of illness: 1-8 days (or slow recovery over 6-8 mts)
! Four types of botulism
! Foodborne
! Infant
! Wound (not related to food)
! A form of botulism whose classification is as yet undetermined
! Neurotoxin cause food intoxication
! High mortality rate
Botulisum
! Clinical signs of intoxication
! Marked fatigue
! weakness and dizziness
! usually followed by double vision
! Progressive difficulty in speaking and swallowing
! Difficulty in breathing, weakness of other muscles,
abdominal distention
! Clinical symptoms of infant botulism
! Constipation
! Poor feeding, lethargy, weakness, pooled oral secretions,
and altered cry
! Loss of head control
! Recommended treatment is primarily supportive care
! Antimicrobial therapy is not recommended
! Infant botulism is diagnosed by demonstrating botulinal
toxins and the organism in the infants' stools.
Infant botulisum
! Infant botulism, first recognized in 1976, affects infants under 12
months of age
! Caused by the ingestion of C. botulinum spores which colonize
and produce toxin in the intestinal tract of infants (intestinal
toxemia botulism)
! Various potential environmental sources such as soil, cistern
water, dust and foods
! Honey is the one dietary reservoir of C. botulinum spores thus far
definitively linked to infant botulism by both laboratory and
epidemiologic studies
! The number of confirmed infant botulism cases has increased
significantly
! It is now internationally recognized, with cases being reported of
infant botulisum related to consumption of honey in infant
Botulisum
! Botulinum toxin causes flaccid paralysis
! Blocking motor nerve terminals at the myoneural junction
! The paralysis progresses symmetrically downward
!the eyes and face, to the throat, chest and extremities
!the diaphragm and chest muscles
! Inhibit respiration and death from asphyxia results
! Recommended treatment for foodborne botulism includes
early administration of botulinal antitoxin
! Intensive supportive care (including mechanical breathing
assistance).
! The incidence of the disease: low,
! The mortality rate is high if not treated immediately
and properly.
! Rare in the United States (< 50 cases per year) (34 cases
in 1994)
Botulism outbreak
! Clostridium botulinum has been associated with
! Inadequately processed, home-canned foods,
! Occasionally commercially produced foods have been
involved in outbreaks
! Sausages, meat products, canned vegetables and seafood
products have been the most frequent vehicles for human
botulism
! Any food that is conducive to outgrowth and toxin
production, that when processed allows spore
survival, and is not subsequently heated before
consumption can be associated with botulism
! Almost any type of food that is not very acidic (pH
above 4.6) can support growth and toxin production
by C. botulinum
Botulisum outbreaks
! In 1987, 8 cases of type E botulism occurred
! 2 in New York City and 6 in Israel
! All 8 patients had consumed an uneviscerated, dry-salted,
air-dried, whole whitefish
! The product was made in New York City and some of it was
transported by individuals to Israel
! All 8 patients with botulism developed symptoms within 36
hours of consuming the food
! One died, 2 required breathing assistance, 3 were treated
therapeutically with antitoxin, and 3 recovered
spontaneously
! The food involved in this outbreak contained high levels of
type E botulinal toxin despite salt levels that exceeded those
sufficient to inhibit C. botulinum type E outgrowth
Botulism case study
! Foodborne botulism due to the consumption of
improperly stored beef stew
! A 47-year-old patient
! Subacute onset of progressive dizziness, blurred vision,
slurred speech, difficulty swallowing, and nausea
! Examination included facial paralysis, palatal weakness, and
impaired reflex
! The patient developed respiratory compromise and required
mechanical ventilation
! Clinical signs:
!Why differential and tentative diagnosis included
foodborne illness ?
Botulism case study
! Diagnosis and treatment
! Anaerobic culture of a stool sample
! Detected type A toxin
! Culture of stool yielded C. botulinum
! Differential diagnoses included wound and foodborne
botulism
! Botulism antitoxin
! Electromyography demonstrated an incremental response to
rapid repetitive stimulation consistent with botulism
! The patient was hospitalized for 49 days, including 42
days on mechanical ventilation, before being
discharged
Botulism case study
! Source of contamination
! During the 24 hours before onset of symptoms
! Patient had eaten home-canned green beans and a stew
containing roast beef and potatoes
! Although analysis of the leftover green beans was negative
for botulism toxin
! type A toxin was detected in the stew
! The stew had been cooked, covered with a heavy lid, and
left on the stove for 3 days before being eaten without
reheating
! No other persons had eaten the stew
Clostridium botulinum
! C. botulinum prevention and control
!Education
!Heat treatment
!Temperatures necessary to kill botulism spores (> 100C for 10
minutes)
!Boiling food for 10 minutes before eating destroys any toxin
present
!Proper storage
!Refrigeration
!Cooked foods should not be held at room temperatures for
hours
! Preservation
!Low acid food
!Chemical: Na nitrite: prevent germination
!Jams and jellies: high sugar content
Isolation of Clostridium botulinum
! To confirm the clinical diagnosis of botulism
! Demonstrate the presence of toxin in the serum or feces of
the patient or in the food
! Mouse neutralization test: 48 hours
! Culturing of specimens: 5-7 days
! Selective media
! Strict anaerobic condition
! Incubate at 30-35 C for 7 days
! Biochemical confirmation
Perfingens food poisoning
Clostridium perfingens
! Gram positive, rod shape
! Spore forming bacteria
! Strict anaerobic bacteria
! Widely distributed in the environment
! Frequently occurs in intestines of humans and domestic
animals
! Spores of the organism persist in soil, sediment (fecal
pollution)
Clostridium perfingens
! Unique characteristic
! Strict anaerobic bacterium
! Produce toxins
!Enterotoxin
!Toxin production in the digestive tract is associated with
sporulation
! Infective dose: high infective dose (>105 CFU/g) (average
108- 109 )
Perfingens food poisoning
! Foodborne toxicoinfection
! Incubation period: 8-20 hrs
! Duration of illness: 12-24 hrs
! Clinical signs
! Intense abdominal cramps
! Diarrhea
! Death as a result of dehydration and other complication
(rare)
! Necrotic enteritis due to the consumption of large number of
organisms
! Deaths from necrotic enteritis (Infection and necrosis of the
intestine and from the resulting septicemia)
Clostridium perfingens outbreak
! Most common: Temperature abuse of prepared foods
! Multiply of organisms during cool down and storage of
prepared food
! Meat and meat products
! Young and elderly are susceptible
! Usually occurs where large quantities of food are
prepared several hours before serving
! CDC estimates that about 10,000 cases occur
annually in the U.S. (Outbreaks may under reported
because the implicated foods or patients feces are not tested
routinely for C. perfingens or its toxin)
Clostridium perfingens case study
! C. perfingens food poisoning associated with Beef
! 1993
! Following long holiday
! 15 persons who become ill after eating beef purchased from
the state fair
! After publicized, 156 persons contact state department of
health
! Symptoms included
!Abdominal cramps
!Diarrhea
!Vomiting
! No persons were hospitalized
Clostridium perfingens case study
! C. perfingens food poisoning associated with Beef
! Questionnaire
! Of 156 reporting illness
!144 (92%) reporting having eaten beef from one vender
! Investigation
!Factors?
!Large demand of food during the state fair
!Vendor purchased 1400 pounds of raw, salt-cure beef
!2- 3 day before the outbreak, portion of beef were boiled for 3
hours
!Allowed to cool down at room temperature and refrigerated
Clostridium perfingens case study
! C. perfingens food poisoning associated with Beef
! Portion of beef were removed from refrigerator
! held in a warmer (48 C)
! Sliced and served
! Sandwiches (beef) held and room temperature until 11.30
a.m. and served
! Culture of samples leftover
! C. perfingens 105 CFU/gm
! Recommendation
! Beef should be divided into small pieces and reheat before
serving (>74 C)
Clostridium perfingens
!Bacillus cereus prevention and control
!Education
!Control cooking temperature
!Rapid cooling
!Bacteria not grow
!Reheat before serving