Gram positive pathogens Flashcards
GI symptoms related to the consumption of food can also be the result of what?
A food allergy (ex. peanuts, tree nuts, milk products, eggs, fish, shellfish, soy, wheat, sesame seeds)
What is the difference between food poisoning and food borne illness?
FBI= infection or toxin-mediated infection or intoxicated AND allergic reaction
Food poisoning= intoxication
What is the single most important aspect of food safety?
Temperature control
What is shelf life?
- Recommended period of time during which a material may be stored and remain suitable for use
- Foods with an atincipated shelf life greater than 90 days are not required to be labeled with a “best before” date or storage information
What is shelf stable?
Foods that can be safety stored at room temperature or “on the shelf”, do not require refrigeration after opening
What foods are shelf stable?
Non-perishable products (ex canned and bottled, jerky, rice, pasta, sugar, spices, oils, etc.)
How are foods shelf stable?
- Heat and/or dried
- Packaged in sterile airtight containers
What virus implicated in FBI has a vaccine?
Hepatitis A
What is FATTOM and what is the significance?
Food- nutrient and protein
Acid- grows best in pH 6.5-8.5
Time- grows more over time
Temperature- higher temperatures
Oxygen- some bacteria need oxygen, some don’t
Moisture- water activity under 0.5 isn’t hazardous (can reduce by adding sugar or salt)
Give an example of when it would be useful for a PHI to know the aw of a food?
Food is dried up and suspected of not having an aw of <0.85 and is held at room temperature or thought to be a food vehicle in an outbreak (ex fermented dried salami)
How does antibiotic resistance spread?
- In animal farming
- In the community
- In healthcare settings
- Through travel
How many gram positive pathogens cause diarrhea in humans?
7 classic gram+ pathogens that cause diarrhea in humans (the rest are gram -)
What are three cocci (spherical) gram positive pathogens?
Stretococcus, Enterococcus, Staphyloccocus
What are four bacilli (rod shaped) gram positive pathogens?
Two produce spores: Bacillus and Clostridium
Two do not produce spores: Corynebacterium, Listeria
Endospores are only formed by 2 genera of gram + bacteria: _____ and ______
Bacillus and Clostridium
Endospores: Sporulation occurs during _____ conditions
Harsh environmental conditions (ex lack of nutrients- starvation)
Endospores: bacterial spores are major __________ contaminants
environmental
Endospores are metabolically dormant resistant to ____, _____, _____, and _____.
heating (boiling), cold, drying, and chemical agents
Endospores: spores become active when exposed to _______
a favourable nutrient of environment
Clostridium perfringens: gram + or -, spore or non-spore forming, anaerobic or aerobic?
Gram +, spore forming rod, anaerobic (but aero tolerant)
Clostridium perfringens: responsible for a large % of _________
Foodborne diarrheal disease worldwide
Clostridium perfringens: reportable and notifiable?
Not reportable in Ontario, not notifiable in Canada
Clostridium perfringens outbreaks are common in Canada:
- Community events and institutions, including hospitals, cafeterias, catering firms, and long-term care facilities
- Likely very under-reported as laboratory does not routinely test for C. perfringens or its toxin
Clostridial Food Poisoning: food poisoning can be caused by _______ produced by _______ in the small intestine
C. perfrigens enterotoxin (CPE), C. perfringens spores
Clostridium perfringen spores can germinate in foods such as _____ and _____
Meats and poultry
Clostridium perfringens: exotoxins can also cause what other infections?
- Clostridial myonecrosis (gas gangrene)
- Clostridial cellulitis
- Enteritis necrotican (pigbel)
- CNS manifestations
C. perfrigens: small numbers of the organisms often are present after the food is cooked due to __________
germination of its spores
C. perfringens: spores survive _____ heat, relatively _____ tolerant
high heat, cold tolerant
C. perfringens: bacteria can grow at temperatures from ____C to ____C and grow _____ quickly
10C to 60C and grow VERY quickly
C. perfringens symptoms
- symptomatic or asymptomatic?
- severe or mild?
- profuse _____ with severe ______
- little or not _____, very few cases with ____ or _____
- recovery usually in _____ hours
- often asymptomatic
- typically relatively mild illness and unnoticed
- bloating and gas
- profuse diarrhea with severe lower abdominal cramps
- little or not vomiting, very few cases with headache or fever
- recover usually in 24 hours
C. perfringens: what is enteritis necroticans or “pig-bel disease”?
- more severe than the other form of the illness, and often fatal
- not found in Canada but in areas where conditions favour the disease
Why does pig-bel disease (clostridial necrotizing enteritis) mostly occur in developing countries ?
- caused by C. perfrigens type C
- mainly affects children with severe malnutrition; rare in Canada but cases have been seen in diabetics
- prevalent globally in 1940s but then disappeared as nutritional status improved in some countries
- called pig-bel disease because was associated with consumption of pig meat
- overall very rare and mainly an issue in areas with severe malnutrition
C. perfringens infectious dose
> 10^6 live vegetative cells or >10^6 spores
C. perfringens type of illness?
- Infection
- Enterotoxin production in the digestive tract
C. perfringens route of transmission?
- food poisoning/intoxication: ingestion of large numbers of vegetative cells present in the food, zoonotic
- no secondary transmission
C. perfringens reservoirs?
- soil, water, air, faeces of healthy and infected individuals, dust, vegetation, gastrointestinal tract of humans and animals, and variety of dehydrated and processed foods
C. perfringens incubation periods?
6-24 hours; median 12 hours
C. perfringens duration of illness?
24 hours, but can last as long as 1-2 weeks
C. perfringens mortaility?
- rare for gastro-enteritis but possible
- enteritis necroticans often fatal
C. perfringens outbreaks?
- often institutions where large quantities of food are prepared and held in the danger zone
C. perfringens diagnosis/treatment?
- feces/supportive care (antibiotics for pigbel)
C. perfringens pH?
5 minimum, 9 maximum
C. perfringens temperature growth range
- approx 10 to 60C
- grows VERY QUICKLY to infectious dose
C. perfringens oxygen
anaerobic (but aerotolerant)
C. perfringens water activity?
0.93-0.95
C. perfringens biofilm formation?
Yes
Factors most contributing to outbreaks?
- allowing foods to remain at room temperature
- slow cooling
- inadequate reheating
- inadequate hot holding
Foods associated with C. perfringens infection include:
- thick soups
- stews
- raw meat, poultry and beef
- meat products
-gravies - dried or pre-cooked foods
- cooked beans
- meat pies
Prevention of C. perfringens
- throughly cook foods to a safe internal temperature
- use a digital food thermometer
- keep food hot after cooking (at 60C)
- microwave reheated foods thoroughly (74C)
- refrigerate perishable foods within 2 hours (at 4C)
- divide leftovers into shallow containers and refrigerate immediately. do not let cool on counter
- do not overstock the fridge to allow circulation of air. ensure thermometer is present in fridge
Why is reheating the last line of defence in preventing C. perfringens outbreaks?
- spores can survive cooking; now they are vegetative cells that can be killed by reheating steps
Why are ‘large’ chunks of meat in the food vehicles in outbreaks rather than thin meats such as hamburgers?
- harder to get adequate internal temperature with larger meats rather than thin
- should divide into small quantities
Clostridium botulinum: Gram ___, ____ forming rod, _____
gram +, spore forming, anaerobic
Clostridium botulinum: ubiquitous _____ spores
heat resisting spores = survives standard cooking and food-processing
Clostridium botulinum: food borne caused by ingestion of ________
highly toxic neurotoxin preformed by the organism growing in food = food intoxication.
C. botulinum: once in digestive tract, neurotoxin is _________
absorbed in the bloodstream
ONE case of botulism = _______ = _______ = ________
outbreak= emergency= immediate notification to province and feds (rare, 4 clinical syndromes)
C. botulinum: potent neurotoxin causes _______
Paralysis
- flaccid paralysis progresses symmetrically downward, usually starting with the eyes and face, to the throat, chest and extremities
C. botulinum: fatal when paralysis involves ________
the respiratory system
C. botulinum: toxin will work its way out of the victim’s system if ________
breathing assistance is provided
C. botulinum: anaerobic milieu, non-acidic pH, low salt, and low sugar content = ________
small number of cases
What pH level of foods can C. botulinum be found in?
low acid foods: pH> 4.5
C. botulinum is _______ in the environment
widely distributed in the environment (ubiquitous)
How many types of botulinum toxin?
7 types (A-G)
A & some B= _______ = ________= _______
proteolytic= break off sulfur groups from proteins= SMELL
Type E & some B= _____ = _______
non-proteolytic = NOT SMELLY
Human cases are caused mostly by toxin __, __, __, and rarely __
A, B, E, and rarely F
Toxin __ and __ cause botulism in animals; Toxin __ and __ cause botulism in birds
C and D; C and E
No outbreaks of type __ have been reported
G
Block acetylcholine transmission across NMJ= _______
neuromuscular blockade and flaccid paralysis
Type __ most common in Canada
85%- Type E, followed by A & B
C. botulinum is formed during growth of _____
vegetative cells
C. botulinum toxin is heat ______
labile
- canning processes developed for prevention of C. botulinum
- all toxins are inactivated by heating to 85C for 5 min (some references say 1 min)
C. botulinum toxin is used for _____ and may cause botulism (unlikely)
botox
What is food borne botulism?
- ingestion of foods containing the toxin produced by C. botulinum
- spores survive in incorrectly or minimal processed foods, then germinate to produce toxin
- improperly processed and inadequately cooked foods (home-preserved foods, low acid) (commercially produced foods)
What is infant botulism?
- ingestion of C. botulinum spores that colonize and produce toxin in the intestinal tracts of infants
- bees may pick up the botulism spores from flowers or soil and the spores are not destroyed in the processing honey
- after the age of one, children’s intestinal bacteria successfully prevent growth of C. botulinum
What is adult intestinal botulism?
- usually preceded by intestinal surgery or altered bacterial gut flora due to the use of antibiotics
What is wound botulism?
- rare
- C. botulinum colonizes in a wound and produces toxins, which read other parts of the body via the bloodstream
- injection drug use, occupational injury (farm)
C. botulinum reportable and notifiable?
Reportable in Ontario and notifiable in Canada
C. botulinum is the _____ reportable enteric disease in Ontario
rarest
C. botulinum: from 2003-2016= ___ confirmed cases in ON
34 cases
- food borne (45%)
- infant (34%) and adult (17%) colonization
- no wound botulism cases, one case unknown
- most cases in older ages= may reflect increased likelihood of preparing and consuming high risk food such as home-canned vegetables
- most food borne cases related to consumed home-canned foods (46%), rarely from contaminated commercial products
- last outbreak= 2012= type E botulism in salted and fermented fish
Foods related to C. botulinum?
low-acid; moist food with pH above 4.6
- some vegetables
- meat and poultry
- seafoods
- soup and milk
- spaghetti sauce with meat, vegetables, and tomatoes
_____ cases of Botulism in Canada in 2019. Most outbreaks in _____ communities.
7 cases; northern communities (Nunavik, northern QC or BC)
Botulism is primarily associated with ____ foods or _____ products
marine mammal foods or canned products
Case fatality of C.botulism has dropped from __% to __% in Canada
17% to 5%
Type A and B= primarily associated with _____
Type E= associated with ____, ____, _____
A and B= canned products
E= fish products, seal, whale meat
Why do fish have high risk for food borne botulism?
- Fesikh prepared salted and fermented fish (common exposure)
- botulism spores are very present in the viscera of fish; difficult in reaching those areas
- salt products create an anaerobic environment; botulism spores can germinate and product toxin
Why are baked potatoes an issue with botulism?
- spores could survive the cooking process
- because cooking potatoes in aluminum foil creates an anaerobic environment
- if left on counter, spores are allowed to germinate and produce toxin
- should unwrap it and expose it to air; keep in fridge until ready to eat
What are C. botulinum GI symptoms?
- nausea
- vomiting
- diarrhea
What are C.botulinum neurological symptoms?
- weakness, constipation, dizziness, general muscle weakness, vertigo, double vision, blurred vision, respiratory paralysis (may result in death), facial weakness, pharyngolaryngeal paralysis
Symptoms for food borne botulism:
- blurred vision
- nausea and vomiting
- fatigue
- weakness and ultimately paralysis
- difficulty swallowing, speaking, breathing
Symptoms for infant botulism:
- same as adult
- loss of appetite
- head control
- constipation
- altered cry
- limited movement of the limbs
C. botulism infectious dose?
extremely small amount- a few nanogram of toxin
C. botulism type of illness?
intoxication- ingestion of toxin, or creation of toxin
C. botulism route of transmission?
- food eaten without sufficient heat or post-production cooking
- no secondary transmission
C. botulism incubation period?
food borne: 18 to 36 hours, 4 hours to 8 days
C. botulism duration of illness?
weeks to months, depending on the severity of illness and promptness of anti-toxin administration
C. botulism mortality?
high CFR if not treated immediately and properly but typically 5-10%
C. botulism outbreaks
primarily sporadic illness; limited outbreaks
C. botulism diagnosis treatment
- serum/stool
- early administration of botulinum antitoxin supportive care
C. botulism pH
- toxin produced at pH >4.8
- group I, type A, B, and F (proteolytic): 4.6 min, 9 max
- group II, type B, E, and F (non-proteolytic): 5 min, 9 max
C. botulism temperature growth range
- group I, type A, B and F (proteolytic): min:10C optimum: 35-40C
- group II, type B, E, and F (non-proteolytic): min 3C optimum: 18-25C
C. botulism oxygen
anaerobic
C. botulism water activity
Group I, type A, B, and F (proteolytic): 0.935
Group II, type B, E and F (non-proteolytic): 0.97
C. botulism biofilm formation
unknown; unlikely
Foods associated with C. botulism
- canned product, smoked and salted fish, garlic in oil, etc.
- low acid foods canned foods (asparagus, green beans, beets, corn, and fish or meat)
- traditional dishes, which are fermented and consumed without cooking
Factors most often impacted to C. botulism outbreaks?
- inadequate time/temp during processing of low-acid foods or
- anaerobic processing of sea mammals (Canada)
How to prevent botulism? (food processing)
- spore inactivation in low-acid foods by heating to 121C for 3 mins
- toxin inactivated by treatment at 85C for 5 min, 80C for 6 min, or 65C for 1.5 hours
- cooling rates that will prevent growth to hazardous levels
- heat resistance of spores decreases at pH values >5 & >9
- reduce pH of food to <_ 4.6
How to prevent botulism at home?
- preparing and canning foods safely
- eliminating unpasteurized honey and peanut butter from the diets of infants
- Covering wounds to avoid contamination with non-sterile substances and soil
- Boiling canned foods for 10 minutes, whether they’re home-made or store-bought
- Abstaining from injection drug use
Do not taste or eat foods from containers that:
- Are leaking
- Have bulges or are swollen
- Look damaged or cracked, or
- Seem abnormal in appearance
What is the issue with vegetables and herbs in oil?
- Anaerobic conditions
- Vegetables or herbs can be contaminated
- Low acid food
- Homemade or retail made; mixtures not provided in ideal environment
Is the botulinum toxin a threat as a bioweapon?
Yes it is a threat; in aerosolized form it produces same symptoms
How can I ensure safe home canning to prevent botulism?
Need high temperature and/or acidic environment to control and eliminate the germination of bacterial spores
