CLOSTRIDIUM Flashcards
What is the causative agent of tetanus?
C. tetani
It is the best know of all anerobic spore-forming bacilli.
C. tetani
Give the morphology of C. tetani.
- Straight slender rod, 0.4-0.6 um x 2-5 um
- Occurs singly in tissues and culture
- Spores: formed after 24-48 hours at ends of rods 2-3x width of the rod (badminton-racket or drumstick-like)
- Gram variable, peritrichous flagella
Give the cultural characteristics of C. tetani.
- Colonies in deep agar fluffy, cottony spheres
- Brush-like effect in gelatin
- Does not ferment CHO
C. tetani is highly resistant to what agents?
Sporicidal agents and technics
How many minutes of boiling are required to kill a C. tetani spore?
15 mins
How many serotypes of C. tetani are present today?
9 serotypes
Give the different types of antigen present in C. tetani.
- Glycopeptide antigen
- Heat labile flagellar antigen
- Somatic antigen
C. tetani is commonly found in what habitat?
- Soil
- Common in horse manure
What are the three toxins emitted by C. tetani?
- Tetanospasmin
- Tetanolysin
- Peripherally active non-spasmogenic toxin
What C. tetani toxin is responsible for characteristic feature of tetanus?
Tetanospasmin
What C. tetani toxin causes local tissue necrosis which is favorable for multiplication; hemolytic for RBC and lethal in lab animals?
Tetanolysin
C. tetani toxins: How many subunits are present in Tetanospasmin?
2
C. tetani toxins: The 2 subunits of Tetanospasmin contains heavy and light chains which are toxic when separated. True or False?
False, non-toxic
C. tetani toxins: Tetanospasmin can be destroyed by what body components?
Gastric juices
C. tetani toxins: Tetanospasmin is heat resistant and poorly absorbed across mucous membranes. True or False?
True
C. tetani toxins: Tetanospasmin is extremely potent. True or False?
True, e.g. LD50 for mice is equivalent to 2x10-8 mg
C. tetani toxins: What is the principle/mode of action of Tetanospasmin in relation to Tetanus?
- Binds gangliosides which are bound to cerebrosides, 2 gangliosides to 1 molecule toxin
- prevents the release of glycine, transmitter substance
responsible for inhibitory nerve network of spinal cord -> prevents contraction of muscle when its opposite counterpart contracts - > continuous stimulation and tetanic spasms of groups of
muscles - Paralytic action on PNS and inactivation of inhibitory nerve network -> inhibition of protein synthesis in brain
- Neuromuscular activity favors migration of toxin along both motor and sensory nerves
- Toxin travels up regional motor nerves where tetanus develops
first -> spreads upward in opposite limbs and subsequently in muscles of the trunk (ascending tetanus) - Tetanus develops first in susceptible motor nerves of the head and neck then descends to voluntary muscles of forelimbs, upper trunk and hindlimbs -> descending tetanus,
usually in humans and horses, affecting nictitating membrane, facial and jaw muscles causing lockjaw or risus sardonicus
C. tetani toxins: Tetanospasmin has longer incubation period and has less severe prognosis. True or False?
False, shorter; worse prognosis
C. tetani toxins: Tetanospasmin is spasmogenic toxin. True or False?
False, non-spasmogenic
Give the portals of entry of C. tetani.
- Nail wounds in horses
- Castration and docking in lambs
- Calving, dehorning, castration, and nose ringing in cattle
- Autointoxication
- Castration in swine
- Wound infection in dogs and cats
- Umbilical cord in newborn
Birds are naturally resistant to C. tetani. Why?
No antibodies, brain has no affinity
How can sheep and goat be immunized against C. tetani?
Neutralizing antibodies
Horse, dogs, pics, and human have antitoxin against C. tetani. True or False?
False, no antitoxins thus the power of binding with toxin
Hyperimmuned serum from horse which has 1500 units protective for 2-3 weeks is one way of C. tetani immunization. True or False?
True
Give the composition of C. tetani vaccine and its doses.
– 0.4% formalin -> precipitated with aluminum potassium sulfate suspended in saline
- 3 doses at 3-week intervals
In horses, toxoids are given in what intervals? How many months can a booster shot be administered?
6 to 8 week intervals followed by 6-12 months later, then annual booster
What are the 2 ways to treat C. tetani infection?
- Antitoxin asap in single IV or intracisternal dose of 100,000 to
200, 000 units - Large doses of penicillin
How do you diagnose C. tetani?
- Characteristic symptoms
- Drumstick-like spores
- Injection to mice
Specie of Clostridium that is a source of potent neurotoxin which causes botulism, a disease characterized by flaccid paralysis and eventual death due to respiratory failure.
C. botulinum
Where is C. botulinum first discovered and from what?
Belgium; imperfectly smoked ham
Give the forms of disease of C. botulinum.
- Intoxication
- Wound infection
- Infant botulism - intestinal colonization
Give the morphology of C. botulinum.
Spores oval, centric and excentric
What is the major metabolic product of all strains of C. botulinum?
Acetic acid
Non-proteolytic type of C. botulinum acidify and coagulate milk. True or False?
False, does not coagulate milk.
Proteolytic type of C. botulinum slowly curdle milk and partially digest darken curd. True or False?
True
All strains of C. botulinum are strict anaerobes but they are not fastidious. True or False?
True
How many serotypes and toxin types of C. botulinum are present today?
6 serotypes; 7 toxin types
What are the hosts of C. botulinum Strain A and the corresponding induced diseases?
- Humans - Botulism
- Cattle, horses - Forage poisoning
- Chicken - Limberneck
- Mink - Botulism
What are the hosts of C. botulinum Strain B and the corresponding induced diseases?
- Humans - Botulism
- Cattle, horse
- Chicken
- Mink
- Foal - Shaker foal syndrome
What are the hosts of C. botulinum Strain C and the corresponding induced diseases?
- Ducks and wild birds - Limberneck, Western duck disease
- Humans - Botulism
What are the hosts of C. botulinum Strain D and the corresponding induced diseases?
- Cattle - Lamsiekte
What are the hosts of C. botulinum Strain E and the corresponding induced diseases?
- Humans - Botulism
What are the hosts of C. botulinum Strain F and the corresponding induced diseases?
- Humans - Botulism
What are the hosts of C. botulinum Strain G and the corresponding induced diseases?
- Humans - Botulism
A complex consisting of toxin molecules and hemagglutiin moiety.
Botulinum toxin
In C. botulinum, toxins of non-proteolytics strains require _____ enzymes such as _____ to fully express its toxic activty.
proteolytic; trypsin
Botulinum toxin is released during ?
Lysis of cells
What are the sources of C. botulinum?
- From ingestion of food contaminated with preformed toxin
- From decaying carcass, ingested or contaminating other food stuffs
It causes depraved appetite for decaying carcasses which leads to the occurrence of botulism.
Aphosphorosis
This syndrome of foal caused by C. botulium infection is characterized by dysphagia, tremors, weakness, recumbency, then followed by death.
Shaker foal syndrome
Give the mechanism of infection of C. botulinum.
Ingestion -> intestinal wall (protected by hemagglutinins from
digestive processes) -> ruminal bacteria inactivate substantial
quantity of ingested toxin -> bloodstream -> peripheral nervous
system -> binds to gangliosides at neuromuscular junction -> inside
surface of cell membrane -> functional change, vesicles
containing acetylcholine no longer able to release AC