Lecture 4 - Clostridum Botulinum And Perfringens Flashcards
What does LUCA mean
Last universal common ancestor
Where are c.bot and perf in phylogenetic tree
Firmicuttes (gram positive)
What re defining characteristics of
OBLIGATE anaerobe.- havent got enzymes to deal with oxygen
- gram + sporulating rod (terminal, subterminal, distend the sporangium) normally TERMINAL
- Neurotoxin - A,B,C1,D,E,F & G
(Mosaic variants (two additional toxins between C and D. Cd,Dc.
How many toxins does a cell normally produce
One but can have more than one. Write like e.g. Af (a IS major toxin but f is minor toxin)
Which macedonian ruler in 886-912 banned the eating of blood sausage to prevent deaths (from c. Bot)
Emeperor Leo VI
Who originally described botulinum as bacillus botulinus after ham outbreak
Van ermengen
Why was it later reclassified to clostridium form bacillus
Bacillus are aerobic
How are 4 groups defied for botulinum
Proteolysis
What toxin type, proteolysis abilities, saccharolysis (sugar breakdown) and disease host does Group I
Tt - A,B,F
P- is proteolytic
S- Negative for saccharolysis
DH - human
What toxin type, proteolysis abilities, saccharolysis (sugar breakdown) and disease host does Group II
Tt- B,E,F
P - Negative
S- positive
Human
What toxin type, proteolysis abilities, saccharolysis (sugar breakdown) and disease host does Group III
tt- C,D
P - weak
S - negative
H- animal
What toxin type, proteolysis abilities, saccharolysis (sugar breakdown) and disease host does Group IV
G
Negative for all others
What about toxin type C and D makes group III particularly problematic
C - poultry
D- bcattle
In silage - if small animals get caught up when farmer mowing get anaerobic condition.
Where is c bot distributed
Soil and water
Particularly E in water as attack fish
Generally in soil - <1 per g
Also found in country more than city - find where animals are
Food outbreaks A, B ( food associated) and E (fish)
Name mesophilic strains of c bot and their requirements
TYPES A AND B
Temp - 10-50deg
PH min 4.7 (some tinned foods arent safe)
Aw >0.94 (doesnt like it too dry)
Name a psychrotrophic strain of c bot
Type E
Temp 3.3-45deg
PH min 4.8
Aw- 0.97
Legal limit for fridge is 8 degrees but this organism grow below.
As pyschrotroph drag left side of the bell curve to the left
As troph will tolerate cold but would prefer heat of 40 deg
Describe activity of botulinum neurotoxin
Exotoxin - produced and secreted outside cell
1- attach to gangliocide receptors
2- bloch Ach release
3- flaccid paralysis
MOST POTENT TOXIN KNOWN
How canbot toxin be destroyed
Heating at 80 deg for ten min
How is botulism toxin used in human life
Used to relax muscles in forehead and face - botox
What are the three main presentations of botulism
Infantile - normally baby lying on back or held by tummy in air make effort to life head up whereas for botulism baby wont lift its head
Foodborne, tinned food big player
Wound - syringes and IV drug use e.g. Heroin spores of clostridia - germinate and produce toxin in situ
Why is c bot not more common
Very poor competitor
What are products of concern for bot
Sous vide - method of preservation (partial cooking then refrigerating)
MAP food - modified atmosphere packaging( plastic base with plastic film mix of gases to preserve but more co2 so bot can grow
Tinned foods - anaerobic in tin - if emerge in tin have time to grow and create toxin
Vegetative cells not very heat resistant but spores are
What temp and duration can c bot withstand
2hr at 100deg
What is incubation, symptoms and duration of foodborne botulism in adults
Incubation 12-72hr
Symptoms:
- nausea, vomiting, sickness, dizziness and headache
- dryness of skin, mouth and throat
- constipation, lack of fever, paralysis
- respiratory failure and death (shut down smooth muscles)
Duration
- 1-10 days
Why is botulism toxin considered most toxic known to man
1mg of toxin can intoxicate 1 million people
When was the last food botulism case reported in uk
2005
Name two big outbreaks of foodborne botulism
Hazelnut yoghurt
Northwest uk 1989 - 25 people got it, 1 died
Tin salmon
Birmingham 1978 -
Where is foodborne botulism a big issue and name some causes
America
50 people cases in spikes
- fermented fish/seafood
- baked potatoes
- chilli sauce
What family in Oregon -1924 had 12 fatalities and why
Gerber family hoemcanned string beans
Americans put meat pates etc and put in water and boil them for home canning e.g. Same as British baking cakes
Why can you not tell when type E toxin strain is present
Non protelytic so make no changes to meat so cannot tell it is there
What is biggest future threat of c bot
Type e strain
Eat lots of salmon, sushi etc that not really cooked so can be used a vesicle
When was last case of infant bot and what age group does infant class as
2011
Infants under 1 year
How is infant bot infective
Ingest spores
Approx 100
Infect via Air, fomites (objects likely to carry an infection e.g. Clothes, utensils)
Lack of gut competitors - produce toxin in gut.
What are Group I strains for infant bot
A, B, Bf and Ba
Not usually fatal
What food cannot be fed to infants under 18 months
Honey
When was last case on wound botulism (injecting) and what other bacteria does it go hand in hand with
2010 3 cases
Anthrax
How is c bot diagnosed
Clinical observation
Tryptose Sulphite Cycloserine (TSC) media
Anaerobic environment
What is the treatment for c bot
Antitoxin - stop progression of disease. Early diagnosis crucial for this but tend to be misdiagnosed
Ventilation for respiratory paralysis
For infantile - self limiting, ventilation.
What is done to prevent c bot
Careful control of canning and preservation
State characteristics for c perf
Gram + Single/pairs RARELY chains Anaerobic Temp 20-50 op 45 U - growth rate = 8-10 minutes Aw >0.93 Spores
What is interesting characteristic for c perf tht differ from other clostridia
Non motile rods
Describe the five biotypes of exotoxin produced by perf
A- E
Four exotoxins - Alpha, beta, epsilon, iota
Enterotoxin - Cpe
Cause profuse diarhoeal disease
Describe spores for c perf
Heat resistant
Freezing sensitive
Dessicatin resistant
What are reservoirs and distribution of perf
Soil, water, food, dust, spices.
Intestines of gut of man and animals
Casseroles, custards, stews, curries, etc - liquids cooked in large volume and allowed yo cool down - cooling process issue
Prepared one day eaten next. Meat dishes food vehicle.
Germinate in cooling phase
What are two main presentations of c perf
Foodborne
- abdominal cramps
- diarrhoea (rarely nausea )
Gas gangrene
- wound infection
- swelling
- tissue necrosis
Describe c perf enterotoxin
Spore specific protein
Heat sensitive 60 deg for 10 min
Toxin formation in intestine - rarely preformed. We eat organism and it produce toxin in us
Large infective dose - 10^8+
What is incubation and duration of c perf food poisoning
Incubation - 6-24hr
Duration 12-24h
Fatalities rare
How many cases of c perf poising predicted
28000
How can c perf be prevented food
Adequate cooking, cooling, reheating
Hot holding
Keep food above 63 degree and below 5 deg to be safe
Is c perf an outbreak or sporadic cases foodborne
Sporadic usually
2011 198 people but likely more
Describe conditions caused by gas gangrene perf
Big in war time. Spores live in soil - little nutrients. Get in wounds.
- Clostridial myonecrosis (production of gas) - N2, Co2, H2 get stuck in muscle cause vacuole holes.
- alpha toxin have ZINC METALLOPHOSPHOLIPASE. Hydrolysis of phospholipids so lead to increased vascular permeability - necrotic
How is c perf diagnose in lab
- clinical presentation and agar
- tsc - tryptose sulphite cycloserine. anaerobic environment, selective supplement (black colonies). Egg yolk, lecithinase action show halo (characteristic of c perf)
What is treatment and prevention of gas gangrene perf
Treatment - debridement. Excision/amputation. Hyperbaric O2 therapy (big chambers, very aerobic - so perf not able to grow).
Prevent gas gangrene - wound management. Take care
