Clostridium tetani

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Clostridium tetani
Clostridium tetani

Clostridium tetani

Systematics
Department : Firmicutes
Class : Clostridia
Order : Clostridiales
Family : Clostridiaceae
Genre : Clostridium
Type : Clostridium tetani
Scientific name
Clostridium tetani
( Flügge 1886) Bergey et al. 1923

Clostridium tetani belongs to the rod-shaped Gram - positive bacteria, is anaerobic and forms endospores . C. tetani (Greek tetanos "spasm") is the causative agent of tetanus ( tetanus ). This bacterium mainly produces the toxins tetanospasmin ,the second most powerful known bacterial poison after botulinum toxin , and tetanolysin .

C. tetani was first discovered independently in 1883 by the Russian surgeon Nestor Monastyrski and a year later (1884) by the German internist Arthur Nicolaier . In 1889 Shibasaburo Kitasato succeeded in isolating and growing C. tetani .

Occurrence

Clostridium tetani occurs ubiquitously in the soil , especially in alkaline soils. Other possible sources of infection are wood and the excretions of cattle and, more rarely, other animal species, but the bacteria are also found in the human intestine . Open wounds can quickly become infected with the bacterium and thus lead to tetanus disease. The common vaccination does not protect against the pathogen itself, but against the tetanus toxin tetanospasmin .

Like all clostridia , C. tetani is anaerobic . The spores, on the other hand, are very resistant and can persist in the soil for years. They are only killed if they are heated for several hours at over 150 ° C; alternatively 24 hours in hydrogen peroxide (6%), formalin (3%), phenol (5%) or chloramine (1%). Simple boiling or a lot of disinfectants are insufficient for this.

The spores are widespread and have also been detected in the intestines and feces of various animals, including humans. They can get into the body through a wound (minor injury such as abrasions, scratches or bite wounds) together with foreign objects such as wood splinters or thorns. A low-oxygen wound environment is required for germination, which can be due to tissue damage or necrosis. When the bacteria then multiply in this environment, they produce the toxins responsible for the danger.

Appearance and properties

C. tetani sporulation

C. tetani is 0.3–0.5 μm wide and 2–2.5 μm long. When the bacteria are cultivated , they form long, filamentous cells. The peritric flagella on the surface give the bacterium its mobility.

C. tetani has a growth optimum between 33 and 37 ° C. If you take into account some strains, the bacterium can grow between 14 and 43 ° C. The sporulation in culture depends on many factors such as temperature, from pH or nature of the medium. It is characterized by the tennis racket-shaped sticks in which the spores are formed at the end. It is used under acidic conditions, high (≥ 41 ° C) or low temperatures (≤ 25 ° C), antibiotics and e.g. B. prevents glucose or potassium. On the other hand, it is stimulated at 37 ° C in the presence of oleic acid , 1–2% NaCl or magnesium. Anaerobic conditions are necessary for germination. B. Lactic acid accelerates.

Pathogenesis

Of C. tetani formed exotoxins are Tetanospasmin and tetanolysin . The importance of the hemolytic tetanolysin has not yet been clarified. The toxin tetanospasmin, which is responsible for the symptoms, is transported along nerve tracts or via the blood to the gray matter of the spinal cord. There it splits synaptobrevin , which is involved in the release of neurotransmitters . As a result, the inhibitory synapses of motor neurons are blocked, so that the nervous system can no longer have an inhibitory effect on the affected muscle . Tetanospasmin therefore acts as a neurotoxin and is considered one of the most powerful poisons known. The minimum lethal dose for humans is estimated to be less than 2.5 ng per kg of body weight. Clinical signs of illness begin with headaches and an increased ability to trigger reflexes. The development of trismus (jaw clamp caused by an increase in the tone of the masticatory muscles), the risus sardonicus (devil's grin, caused by the contraction of the facial muscles) and cramping of the extensor muscles of the trunk, called opisthotonus , as well as extension cramps of the trunk and extremities, which are caused by external stimuli, follow gradually be favored. These signs increase and can become extremely painful when muscles are clonically contracted and ultimately the patient is supine and only resting on the head and heels. Spinal fractures have also occurred as a result. For a detailed description of the symptoms of tetanus see there.

therapy

The treatment of tetanus carried out for a further by treatment of the excitation source or toxins by surgical wound revision with extensive debridement . In addition, high doses of penicillin or broad-spectrum antibiotics are given, as there is often a mixed infection. In the case of deep, soiled wounds and basic immunization, and the last booster more than 5 years ago, active immunization with tetanus toxoid is carried out. If the basic immunization is incomplete within the last 10 years or if the vaccination status is unclear, a combined active (tetanus toxoid) and passive (hyperimmunoglobulin) immunization is carried out. No prophylaxis is required if you have had a basic immunization or a booster in the last 5 years.

literature

  • M. Frink, CW Muller, S. Ziesing, C. Krettek: Tetanus prophylaxis in the emergency room. In: trauma surgeon. 109 (11), 2006 Nov, pp. 977-983. PMID 17021900

Web links

Individual evidence

  1. ^ A b F. Hofmann: Tetanus. From: Vaccination Compendium . Ed .: Heinz Spiess, Ulrich Heininger, Wolfgang Jilg. 8th edition. Georg Thieme Verlag, 2015, ISBN 978-3-13-498908-3 , p. 272 ff .
  2. ↑ Tetanus. In: Epidemiology and Prevention of Vaccine-Preventable Diseases. Centers for Disease Control and Prevention, 2006, accessed April 11, 2019 .
  3. ↑ CPT: CliniPharm / CliniTox. Retrieved April 11, 2019 .
  4. ↑ Treating clostridia - My experiences: nutrition, probiotics / prebiotics ... In: Chronic healing. July 9, 2015, accessed on April 11, 2019 (German).
  5. ↑ Clostridium tetani - Infection, Transmission & Diseases | MedLexi.de. Retrieved April 11, 2019 .
  6. ↑ a b c d e BENEFIT DOCUMENTATION OF STANDARD VACCINES: TETANUS. Arznei-Telegram , February 19, 2016, pp. 17-20 , accessed on October 12, 2019 .
  7. ↑ a b c d e Stanley A. Plotkin et al .: Plotkin's Vaccines . 7th edition. Elsevier, Philadelphia 2017, ISBN 978-0-323-35761-6 , pp. 1052 ff . ( elsevier.com ).
  8. ↑ Arne C. Rodloff: Obligatory anaerobic, spore-forming rods (clostridia) . In: Sebastian Suerbaum, Gerd-Dieter Burchard, Stefan HE Kaufmann, Thomas F. Schulz (eds.): Medical microbiology and infectious diseases . Springer-Verlag, 2016, ISBN 978-3-662-48678-8 , pp. 324 , doi : 10.1007 / 978-3-662-48678-8_39 .