G

The spores are round in shape, with a diameter larger than the bacterial body, and are located at the top of the bacterial body

stick-like

strictly anaerobic

Easy to migrate and spread on the surface of the culture medium, with B hemolytic rings and feather-like colonies

Does not ferment sugars and does not break down proteins

Invasion route

Important conditions for infection to occur

Not invasive

Exotoxins

Clostridium tetanus spores infect the wound → an anaerobic microenvironment is formed locally in the wound, and the spores germinate → produce tetanus spasm toxin and enter the blood → the heavy chain acts on the neuromuscular junction motor neuron cell membrane → endocytosed into synaptic vesicles and along the nerve The axon travels retrogradely and transports toxins to the inhibitory nerve cytoplasmic endosomes in the anterior horn of the spinal cord → releases light chains → prevents the release of inhibitory neurotransmitters (y-aminobutyric acid and glycine) from the presynaptic membrane → tonic spasms

tetanus

neonatal tetanus

Humoral immunity

Spasmotoxin is very toxic and can cause disease in very small amounts, so it is not enough to effectively stimulate the immune system to produce TAT.

prevention

treat

G

The oval diameter of the spores is smaller than that of the bacteria and is difficult to observe.

Anaerobic (not strict), short division cycle (8 minutes per generation), active metabolism

Blood agar plate—double layer hemolysis ring

Egg yolk agar plate (Nagler reaction) - milky white turbid circle

Milk culture medium—turbulent fermentation

Meat cooking medium (based on all anaerobic bacteria) - produces a lot of gas, the meat residue is light pink

Types

Pathogenic substances

Disease caused

Direct smear microscopy – valuable rapid diagnosis

surgical debridement

antibiotic treatment

hyperbaric oxygen chamber method

The oval diameter of the spore is larger than that of the bacterium and is located at the secondary end, giving the bacterium a spoon shape.

botulinum toxin

After entering the small intestine, it is absorbed into the blood circulation and acts on peripheral cholinergic nerves.

The heavy chain binds to the receptor and forms toxin-containing synaptic vesicles in the cytoplasm, which are retained at the neuromuscular junction and fuse with endosomes

Light chain dissociation, zinc endopeptidase activity, inhibits acetylcholine release at the neuromuscular junction, leading to flaccid paralysis

foodborne botulism

infant botulism

traumatic botulism

iatrogenic botulism

inhalation botulism

specimen

Animal experiment

Similar to tetanus