Clostridium tetani

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A Microbial Biorealm page on the genus Clostridium tetani

Classification

NEUF2011 Kaitlyn Bergeron, Patrick Barrett, Jaclyn Egitto, Alexander Mastriano

Higher order taxa

Bacteria; Firmicutes; Clostridia; Clostridiales; Clostridiaceae

Species

Clostridium tetani

Description and significance

C. tetani is a bacillus, or rod-shaped bacterium. The bacteria is Gram positive and commonly takes the shape of a drumstick when Gram stained. This drumstick appearance is due to the spore formation that occurs inside the cell. C. tetani is known for causing tetanus. Spores of the bacterium enter the body through open wounds and germinate once inside. C. tetani move around by the use of rotary flagella. The organization of these flagella is peritrichous, which means there are flagella randomly assorted around the cell. These bacteria are found in many different environments, most commonly in soil, dust, animal intestines, and in animal feces. They are obligate anaerobes and thus rely on fermentation and cannot tolerate the presence of oxygen.

Genome structure

The genome of C. tetani consists of one chromosome of 2776 genes. All but one of these genes are protein-coding genes (99.96%). There are 2,799,25 base pairs in the genome encoding 2,372 open reading frames. The tetanus toxin is located on the pE88 plasmid. The gene for the toxin is called tetX and is located next to a gene encoding a collagenase called colT. There 74,082 base pairs in the pE88 plasmid that codes for the toxin.

Cell structure and metabolism

C. tetani is a gram-positive bacterium, which means it has a thick cell wall made up of multiple layers of peptidoglycan. It has only one cell membrane, which is located on the inside of the cell wall. C. tetani produces and secretes mamny enzymes that break down susbtances in the environment, including proteins, fats , and carbohydrates. They are able to convert these sustances into chemicals they can use for energy.

Ecology

C. tetani is found mostly in warm, damp areas, especially in manure treated soil, but can also be found in the intestines or feces of many animals, such as horse, sheep, and dogs. In its vegetative state C. tetani is heat sensitive and cannot survive in the presence of oxygen. However its spores are resistant to heat and some antiseptics, but oxygen rich areas are also toxic to them. When in soil, they can last for months or even years in the proper conditions.The spores can germinate through the dead cells of the body, thus spreading toxins.

Pathology

C. tetani enters its host (usually humans) through open wounds, lacerations, or burns where many cells are dead and lack oxygen. This provides the necessary environment for C. tetani to begin to spread its virulence factors. Once inside the dead cells, the bacterium germinates. All strains are found to produce the toxin tetanospasmin, which blocks the release of necessary neurotransmitters in the central nervous system's transmission of inhibitiory nerve impulses. As a result of these blocked neurotransmitters, the body experiences muscle spasms at the site of the infection.

Current Research

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Cool Factor

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References

[Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500.

Edited by student of Iris Keren