Bacillus Spp. / Neurogenic Clostridium Spp Flashcards
What are the types of bacillus that we are studying?
Bacillus
Bacillus anthracis
Bacillus cereus
Bacillus thuringiensis
How are bacillus normally present when seen on slides?
Rods, in pairs or long chains
Bacillus is widely distributed in the environment
Endospores can survive more than 50 years
Resist desiccation, high temperatures, and chemical disinfectants
Is bacillus oxidase positive or negative? is it catalase positive or negative? Is it motile? Are most pathogenic? Do they produce endospores? What kind of media can they grow on?
What does it mean if a bacteria is oxidase positive?
Oxidase positive bacteria possess cytochrome oxidase or indophenol oxidase (an iron containing haemoprotein). Both of these catalyze the transport of electrons from donor compounds (NADH) to electron acceptors (usually oxygen). The test reagent, N, N, N’, N’-tetramethyl-p-phenylenediamine dihydrochloride acts as an artificial electron acceptor for the enzyme oxidase. The oxidized reagent forms the coloured compound indophenol blue.
What are some features of B. anthracis, and B. cereus?
What are features of bacillus antracis?
Colonies up to 5 mm in diameter, flat, dry, greyish appearance (medusa head at edge of the colony) No hemolysis
What bacillus bacteria is seen in this image?
Bacillus anthracis
What bacillus bacteria is seen in this image?
Bacillus anthracis
What bacillus bacteria is seen in this image?
Bacillus anthracis
What bacillus bacteria is seen in this image?
Bacillus cereus
What bacillus bacteria is seen in this image?
Bacillus cereus
What are features of bacillus lincheniform?
Bacillus licheniform: Colonies are dull, rough, wrinkled and strongly adherent to the agar
What bacillus is seen in this image??
Bacillus licheniform
What are features of bacillus cereus?
Bacillus cereus: Colonies similar to B. anthracis but larger with a greenish tinge Hemolysis around the colony
What is the clinical manifestation of B. anthracis in cattle, sheep?
Fatal peracute or acute septicaemic anthrax
What is the clinical manifestation of B. anthracis in pigs?
Subacute anthrax with oedematous swelling in pharyngeal region; an intestinal form with higher mortality is less common
What is the clinical manifestation of B. anthracis in horses?
- Subacute anthrax with localized oedema; septicaemia with colic and enteritis sometimes occurs
What is the clinical manifestation of B. anthracis in humans?
Skin , pulmonary and intestinal forms of anthrax are recorded in humans periodically.
What is the clinical manifestation of B. cereus in cattle?
Mastitis (rare)
What is the clinical manifestation of B. cereus in humans?
Food posioning/ eye infections
What is the clinical manifestation of B. licheniformis in cattle, sheep?
Sporadic abortion
What is the epidemiology of Bacillus?
Endospore -> alkaline soils, rich in Ca and N-> Contaminated pastures, buried carcasses-> Ingestion of spores, inhalation or through the skin
What is the pathogenesis of Bacillus?
Capsule provides resistance to phagocytosis
Toxins components: Protective antigen (binding moiety), oedema factor and lethal factor.
Neutrophils is the target of the oedema factor.
Macrophages, dendritic cells neutrophils and some epithelial and endothelial cells are
the target of the lethal factor
What are the clinical signs of Bacillus?
Clinical signs: Cattle and sheep are more susceptible, fever, depression, congested mucosae and petechiae, abort.
What are the lesions caused by Bacillus?
Lesions: rapid bloating, incomplete rigor mortis, ecchymotic hemorrhages and oedema, dark, unclotted blood and blood stained fluids in cavities, extremely large soft spleen (main characteristic in cattle).
How do you diagnose Bacillus?
- Presence of unclotted blood in mouth, nostrils and anus.
- Do not open the carcasses.
- Blood sample or fluids Gram staining
- Bacterial culture Blood agar: 37C, 24-48h.
- PCR
- Ascoli test, precipitation or gel diffusion
How do you treat cases of Bacillus?
- Penicillin, oxytetracyclin
How do you control Bacillus in endemic regions?
Annual vaccination –> Sterne strain, live vaccine, the spores convert in non-encapsulated avirulent
vegetative organisms.
How do you control Bacillus in non-endemic regions?
- Avoid movement of animals
- Personnel must wear PPE
- Foot baths (formalin + peracetic acid)
- Immediate disposal of carcasses
- Lock all buildings and fumigate with formaldehyde)
What are the characteristics of clostridiums?
• Characteristics
• Straight or slightly curved rods
• Produce endospores. The size, shape and location of the endospores can be
used for species differentiation. • More than 100 species but less than 20 are pathogenic.
Clostridial cultures typically emit ____ ____
putrid odors
In clostridium what is the most common mode of energy production?
Peptide catabolism is the most common mode of energy production by clostridiums
What are the key characteristics of clostridium?
What are saprophytes?
Clostridia are saprophytes, they constitute part of the normal intestinal flora and some may be sequestered as endospores in muscle or liver. Sequestered endospores, if activated, may produce disease.
What are the histotoxic clostridia?
What are the enteropathogenic and enterotoxaemia producing clostridia?
What is the atypical clostridia organism?
C. piliforme
What are the neurotoxic clostridia?
What are the features of clostridum tetani and clostridium botulinum?
What are the the serological types of Clostridium tetani?
Ten serologic types
• Based on flagellar antigens
• Sometimes related to geographic strain origin
• TeNT is antigenically uniform
• HUGE IMPORTANCE FOR VACCINE!!!
Clostridium tetani is widely distributed in ____ and is often transient in the ____
soil, intestine
What can be attributed to the occurance of tetanus?
• Occurrence is linked to the introduction of the spore into traumatized tissue
How can you contract tetanus?
- Contaminated syringes!!!!
- Penetrating nail wounds of the foot
- Barnyard surgery
- Use of rubber bands for castrating and docking sheep
- Ear tagging infections
- Shearing wounds
- Post-partum uterine infections
- Peri-natal umbilical infections
- Small animal fights
Tetanus is a _______ intoxication characterized by ?
• Neuroparalytic intoxication characterized by tonic-clonic convulsions
Tetanus is due to ?
protein neurotoxin
Who is susceptible to tetanus?
All mammals are susceptible (varying degrees)
• Horses and humans, ruminants, and swine more susceptible
than carnivores
• Poultry highly resistant
• In all animals, the mortality rate is high
What is the Tetanus toxin (tetanospasmin) and how does it affect the body?
- Tetanus toxin (tetanospasmin)
- Zinc endopeptidase binds to the neurons, which release gamma-aminobutyric acid (GABA) and glycine, the major inhibitory neurotransmitters
- Hydrolyzes the docking proteins (VAMP aka synaptobrevin) required by neurotransmitter-containing vesicles to fuse with the pre-synaptic membrane
- Once the docking proteins are hydrolyzed, the synapse degenerates, taking weeks-months to regenerate
What is the pathogenesis of tetanus?
anerobic environment allows spores to generate -> toxin diffuses via vascular channels or peripheral nerve trunks. -> Toxin attaches to receptors on the nearest colinergic nerve and is internalized within a vesicle -> vesicle travels retrograde inside in the axons to the cell bodies in the ventral horns of the spinal cord -> toxin causes the innervated muscles to remain in sustained clonic or tonic spasms. Toxin tracels within the cord to the othe levels affecting additional muscle groups.
- Spastic paralysis
What are the disease patterns of Tetanus?
Early signs, following an incubation period of a few days to several weeks are:
• Stiffness, muscular tremor, and increased responsiveness to stimuli
• Mortality is at least 50% and highest in the young animals
What are the signs and symptoms of tetanus in horses, ruminants, and swine?
• Signs include:
• Retraction of the third eyelid, erectness of ears, grinding of teeth and
stiffness of the tail
• Bloat is common in ruminants
• Feeding becomes impossible (Lockjaw)
• Rigidity of extremities cause “Sawhorses” attitudes and eventually
recumbence
• Fecal and urinary retention, sweating and high fever
• Consciousness persists
• Death, due to respiratory arrests, occur in lambs and piglets within the
first week, in adult animals in 1-2 weeks
• Full recovery requires weeks to months
What bacteria casues the issues you see in this image?
Tetnas
What causes this presentation in cats?
Tetnas: Rigid hind leg
What is seen in this image?
The source of the tetanus infection,
with the other cat’s tooth
What can be seen in this image?
A poor puppy with tetnas
What can be seen in this image?
A horse with tetnas
What can be seen in this image?
A poor pup with tetnas
What are the immunologic aspects of Tetanus?
• Acquired resistance depends on circulating antitoxin
• Survivors are susceptible to re-infection
• Not enough toxin present to induce a strong immune-response
(neutralizing antibodies)
• Passive and active protection is provided by administration
of antitoxin or immunization with toxoid
What laboratory diagnostics are used for tetanus?
• Gram-stain smear from suspected wound may reveal the
typical “drumstick” type bacteria
• Wound exudate is plated on Blood agar in anaerobic
culture
• Hemolytic due to tetanolysin
• Drop of antitoxin will inhibit hemolysis
• Injection of suspected isolates can be injected into two
mice (One received antitoxin)
• Molecular diagnosis (PCR) can be used to support
How do you treat a patient with tetanus?
• Therapy aims at:
• Neutralization of circulating toxin
• Injection of adequate dose of antitoxin
• 10,000-300,000 units for horses
• Suppression of toxin production
• Wound care and large doses of parenteral penicillin or metronidazole
• Flushing of hydrogen peroxide to create aerobic conditions
• Life support and symptomatic relief to the patient
• Use of sedatives and muscle relaxants and exclusion of external stimuli
• Artificial feeding by stomach tube or intravenously may by necessary
after the hyperesthetic phase
• Nursing care is most important
How do you prevent Tetanus?
• Wounds should be properly cleaned and dressed
• During surgical procedures appropriate hygienic precautions should be
observed
• Especially on mass scale under farm conditions
• Horses unless actively immunized, are given antitoxin after injury or surgery
and/or penicillin
• Active immunization employs formalinized toxoid given twice at 1-2 month
intervals and annually thereafter
• Passive immunity passes from immunized mares to nursing foals and appears to
provide protection for about 10 weeks, when toxoid can be given.
_______ ____ causes Botulism
Clostridium botulinum
What clinical sign characterizes clostridium botulinum? What is the cause of intoxication?
• Neuroparalytic intoxication characterized by FLACID PARALYSYS ‘
• Intoxication caused by any of the seven protein neurotoxins
• A to G
• Type G has been renamed C. argentinense • C and D are the most common in domesticated animals • Identical in action but differ in potency, antigenic properties and
distribution
What animals do Botulism usually affect ?
mainly ruminants, horses, mink, and fowl (waterfowl)
• Swine, carnivores and fish are rarely affected
Where can type A C. botulinum toxins be found? Who can they affect?
Where can type B C. botulinum toxins be found? Who can they affect?
Where can type C C. botulinum toxins be found? Who can they affect?
Where can type D C. botulinum toxins be found? Who can they affect?
Where can type E C. botulinum toxins be found? Who can they affect?
Where can type F C. botulinum toxins be found? Who can they affect?
Where can type G C. botulinum toxins be found? Who can they affect?
Where to botulinum neurotoxins act? What endopeptidases have identical activity? What is the goal of these endopeptidases?
Botulinum neurotoxins (BoNT)
• Act in the neuromuscular junction
• Zinc endopeptidases with identical activity that binds to
cholinergic nerve cells
• Decreases the release of acetylcholine
• Once hydrolyzed, the synapse degenerates, taking weeks to months
to regenerate
• BoNT are secreted with accessory proteins
• Aid in the survival in the GI tract
BoNT are secreted with ______ proteins
• Aid in the survival in the ___ tract
accessory,
GI
What is a reservoir for Botulism?
• Soil and aquatic sediments
• Vehicles of intoxication are contaminated animal and plant material
• When animals die, the spores (common in gut and tissues) germinate
and generate toxin, which may be ingested by carrion eaters or
contaminated environment
• Contaminated cans of meat and vegetables
How is Botulism transmitted?
- Toxin ingestion
- Spore ingestion (Important in human infants botulism)
- Wound contamination (rarely in humans and horses)
What is the cause of death in botulism?
•When it affects muscles of respiration ➢Death due to respiratory failure
What is the pathogenesis of Botulism?
BoNT are ingested and absorbed in the GI tract -> Circulates in the blood stream -> neuro muscular junction of cholinergic nerves -> hydrolyzes a docking protein (synaptobrevins and other SNARE) -> Synapses degenerates and flaccid paralysis result due to lack of neurotransmitter ( acetylcholine)
•When it affects muscles of respiration ➢Death due to respiratory failure
What are the clinical signs of Botulism?
- Muscular incoordination leading to:
- Recumbency
- Extrusion of the tongue
- Disturbances in chewing and swallowing food
What happens to a patient’s consciousness in cases of Botulism?
No changes in consciousness occur
How is patient temperature affected if they have Botulism?
Temperature remains normal
• Unless secondary infections occur (Pneumonia)
Describe the recovery process in nonfatal cases of botulism.
In nonfatal cases, recovery is slow and residual signs may persist for months
What is occuring in this image of a cow?
- dairy cow has end stage botulinum toxicosis
What is this cows position ? What is the cause?
Sternal recumbency
Botulism
What is this cows position ? What is the cause?
Lateral Recombancy - Botulism
What is this sheeps position ? What is the cause?
Sternal Recombancy- Botulism
What is this cows position ? What is the cause?
Lateral recombancy - Botulism
What is this cows position ? What is the cause?
Sternal recombancy - Botulism
What is the cycle of avian botulism? Where do you not find lesions? What are typical clinical signs?
- Toxin production takes place in decaying animal carcasses -> maggots concentrate toxins-> toxins are ingested-> death and additional toxin production -> cycle accelerates- major die off occurs.
Live animals have flaccid neck paralysis.
No gross lesions in brain or muscles.
What is occuring in this image?
Flaccid neck paralysis.
What is seen in this image?
Hen with botulism
• Limberneck
• Initial clinical sign of botulism
What are the laboratory diagnostic processes for botulism?
• Requires demonstration of the toxin in plasma or tissue
before death or from a fresh carcass.
• Isolation of the organism is not definitive.
• Demonstration of toxin in feedstuffs, fresh stomach
contents, or vomit.
What are the steps of lab diagnosis of Botulism?
• Toxin is extracted from material and injected into guinea
pigs or mice
• Still the only accepted method of confirmation
• Death occur within 10 h – 3 weeks (average 4days)
• Death is preceded by muscular weakness, limb paralysis, and
respiratory difficulties
• Any toxin must be neutralized by one of the C. botulinum
antitoxins
How can you isolate botulism from a sample ?
• Isolation is possible
• Heat samples 65-80°C for 30 min to induce germination and
culture anaerobically on Blood Agar
How can you support a Botulism diagnosis?
• Serological and molecular techniques are available to support the diagnosis
What is occuring in this image? What does it indicate?
Egg yolk agar showing the lipase
reaction after 72 hours of incubation
Growth of Clostridium botulinum
What is seen in this image?
Colony grown on a 72 hour blood agar plate of Clostridium botulinum
What would you do in a case of recent ingestion in botulism?
Recent ingestion
• Evacuation of the stomach and purging is helpful
How would you treat a patient with botulism?
Antitoxin treatment following onset of signs is sometimes beneficial
• Mainly in minks and ducks
Animals at risk of contracting Botulism should?
be vaccinated with toxoids (A-D)
What are some other forms of treatment and control for Botulism?
- Polyvalent antiserum
- Removal of affected waterfowl to dry land saves many birds from exposure and drowning
- Placing feed on dry ground attracts birds from contaminated areas
- Guanidine and tetraethylamide stimulates acetylcholine release
- Vaccination (Toxoid) in endemic areas
What is botox?
ITS TOXIN.WTF
