Clostridium botulinum

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Clostridium botulinum
Clostridium botulinum

Clostridium botulinum

Systematics
Department : Firmicutes
Class : Clostridia
Order : Clostridiales
Family : Clostridiaceae
Genre : Clostridium
Type : Clostridium botulinum
Scientific name
Clostridium botulinum
( van Ermengem 1896) Bergey et al. 1923

Clostridium botulinum is a gram-positive , rod-shaped bacterium from the endospore-forming family of the Clostridiaceae . The diameter is 0.5–1.0 µm with a length of 2–10 µm. The spores are oval, usually arranged subterminally and often wider than the mother cell. Although it is an anaerobic bacterium, it is relatively insensitive to atmospheric oxygen. It was first isolated by the Belgian microbiologist Emile van Ermengem in 1897, who initiallysuggestedthe name Bacillus botulinus . The isolation from sausage ( lat. Botulus ) and the connection with the already known clinical picture botulism ,which was proven for the first time, gave the product its name.

C. botulinum consists of different biochemically different groups, the only thing they have in common is the formation of botulinum toxin . Various toxins (A, B, C 1 , C 2 , D, E, F and G) are formed, only those of types A, B, E and F are pathogenic to humans . Types C and D are pathogenic for animals . There are only a few case reports in humans for the rare type G toxin . However, some strains of Clostridium butyricum and Clostridium baratii also produce botulinum toxins. Closely related clostridia, which however do not produce botulinum toxin, have been classified taxonomically under the name Clostridium sporogenes .

groups

Since the taxonomy is based exclusively on toxin formation, the species includes organisms with a wide variety of metabolisms , which are divided into four phenotypic groups. Sequencing of the 16S rRNA and nucleic acid hybridization reactions have confirmed the four lineages.

Classification according to phenotypic differences
Group: I. II III IV
Toxin type: A, B, F B, E, F C, D G
Proteolysis: Yes No No Yes
Lipase: Yes Yes Yes No
Fermentation: Glucose, partly fructose, partly maltose Glucose, fructose, mannose, maltose, sucrose, trehalose Glucose, partly fructose, mannose, partly maltose
Acid formation: Acetic acid, iso-butyric acid, butyric acid, iso-valeric acid Acetic acid, butyric acid Acetic acid, propionic acid, butyric acid Acetic acid, iso-butyric acid, butyric acid, iso-valeric acid, phenylacetic acid
Growth optimum: 35-40 ° C 18-25 ° C 40 ° C 37 ° C
Heat resistance of the spores: 112 ° C 80 ° C 104 ° C 104 ° C

toxin

The seven toxin types (A to G) can be distinguished serologically by neutralization with an antitoxin. Some strains form mixtures of two neurotoxins.

Types of Clostridium botulinum and species affected by disease
Type mainly affected species most common delivery vehicle
A. Human (also wound and infant botulism), chickens homemade preserves with vegetables, fruits, meat and fish
B. Humans (including wound and infant botulism), horses, cattle processed dishes (especially pork products)
C α Waterfowl decaying vegetation of alkaline swamps, invertebrates
C β Cattle, horses toxic food, carrion, pork liver
D. Bovine Carrion
E. Human, fish, waterfowl Fish and other sea products
F. Human (also infant botulism) Meat products
G unknown ground

Remarks

  1. ↑ Type C α strains produce both the neurotoxin C1 and the toxic but not neurotoxic C2. The latter is fatal to mice, ducks and geese. Birds injected with the C2 toxin developed congestion and bleeding in the lungs, but lacked paralytic signs of botulism.
  2. ↑ Type C β strains only produce C2 toxin.

In addition to the seven generally recognized "classic" types, several novel toxin types were postulated or found, such as a type H (which was later recognized as a hybrid of types A and F) and a type X.

If Clostridium botulinum toxins are absorbed from the intestine into the blood, they reach the peripheral neuromuscular synapses. Here BTX is absorbed endoneurally and blocks the release of the neurotransmitter acetylcholine . The death rate is highest for type A, followed by type E and then type B, which may be explained by the affinity for binding to the nerve tissue. Type A toxin is used therapeutically to treat unwanted muscle spasms and some focal dystonias .

Pathogenesis

The best known form is food poisoning from botulinum toxin. In contrast, wound botulism, in which the pathogen grows in dead tissue, is rather rare. In infant botulism, the spores are ingested and germinate in the intestinal tract, where toxin production occurs. Initially, the cranial nerves are affected, which affects vision, hearing, and speech. Typical are double and blurred vision, dilated pupils and indistinct pronunciation. Decreased saliva production will keep your mouth dry and make swallowing painful. Later the motor nerves are paralyzed, which is expressed in a general feeling of weakness. Death occurs through paralysis of the respiratory muscles or cardiac arrest.

Epidemiology

The spores are also found worldwide in water sediments and in small quantities in the gastrointestinal tract of birds, fish and mammals. Toxin type A is common in the US and type B in Europe.

Food hygiene

In hermetically sealed tinned meats, especially sausages, fish, vegetables, fruits or spices, the spores can germinate and produce toxins. Insufficiently heated, self-canned food is particularly affected, as Clostridium botulinum is not reliably killed at temperatures of up to 100 ° C. Children under 1 year of age should not consume honey as it may contain spores that can trigger infant botulism. Other sources of input are dust and earth.

Studies regarding the contamination of corn (starch) syrup with Clostridium botulinum spores are contradictory. In an investigation from 1982, a contamination level of 50 spores per gram was found in 1.3% of the corn syrups tested; in a later investigation (1988) no spores were found in 43 samples of syrups of different origins, in 1991 no spores in 738 samples of corn syrup or products containing it.

Maple syrup can contain microorganisms that have multiplied, including Clostridium botulinum , due to the dust it is exposed to during extraction and further processing .

Diagnosis

C. botulinum on AEY agar with iridescent halo formation ( lipase reaction)

To distinguish whether a proteolytic or non-proteolytic strain is present, cultivation can be carried out on calf liver and egg yolk agar or anaerobic egg yolk agar (AEY). The colonies become iridescent when the light falls at an angle, but they cannot be distinguished from non-toxic clostridia. Enrichment can take place in tryptone-peptone-glucose-yeast extract medium (TPGY) or cooked meat medium (CMM).

The toxin can then be detected using a mouse bioassay , whereby the test animals are injected with a dilution series into the diaphragm and the typical symptoms of botulism (respiratory paralysis, wasp waist) are observed. To determine the toxin type, some test animals are given the respective antitoxins beforehand. In Germany, the mouse bioassay is the reference method according to § 64 LFGB for official food control. In practice, however, animal experiments are largely replaced today by modern real-time PCR of human pathogenic toxin genes ( bont A, B, E, F).

An amplified and a DIG ELISA are also possible.

Reporting requirement

In Germany, direct or indirect evidence of the bacterium or toxin must be reported by name in accordance with Section 7 of the Infection Protection Act if the evidence indicates an acute infection. The obligation to notify primarily concerns the management of laboratories ( § 8 IfSG).

In Switzerland, the positive and negative laboratory analysis findings to the exciter is notifiable and that after the Epidemics Act (EpG) in connection with the epidemic Regulation and Annex 3 of the Regulation of EDI on the reporting of observations of communicable diseases of man . This reporting obligation applies to laboratories.

Individual evidence

  1. ↑ Kenneth Todar: The Pathogenic Clostridia; in: Todar's Online Textbook of Bacteriology , Univ. of Wisconsin-Madison Department of Bacteriology, 2005
  2. ↑ Johannes Krämer: Food microbiology . 5th edition. UTB, Stuttgart 2002, ISBN 3-8252-1421-4 , pp. 67 .
  3. ↑ Emile van Ermengem: About a new anaerobic Bacillus and its relationship to botulism . In: Medical Microbiology and Immunology . tape 26 , no. 1 , 1897, p. 1-56 , doi : 10.1007 / BF02220526 .
  4. ↑ BfR : Information for consumers on botulism (PDF; 107 kB).
  5. ↑ a b c d e Samuel Baron (Ed.): Medical microbiology . 4th edition. Galveston 1996, ISBN 0-9631172-1-1 , PMID 21413252 ( full text - Botulism and Clostridium Botulinum ).
  6. ^ Judicial Commission of the International Committee on Systematic Bacteriology: Rejection of Clostridium putrificum and conservation of Clostridium botulinum and Clostridium sporogenes Opinion 69. In: International Journal of Systematic Bacteriology. 49, 1999, p. 339.
  7. ↑ a b c d Collins MD, East AK: Phylogeny and taxonomy of the food-borne pathogen Clostridium botulinum and its neurotoxins . In: J Appl Microbiol . tape 84 , no. 1 , 1998, p. 5–17 , doi : 10.1046 / j.1365-2672.1997.00313.x (English).
  8. ↑ Jason R. Barash, Stephen S. Arnon: A Novel Strain of Clostridium botulinum That Produces Type B and Type H Botulinum Toxins. J Infect Dis. (2013), October 7, 2013, doi: 10.1093 / infdis / jit449 .
  9. ↑ SE Maslanka et al .: A novel botulinum toxin, previously reported as serotype H, has a hybrid structure of known serotypes A and F that is neutralized with serotype A antitoxin. J Infect Dis Volume 213 (2016) pp. 379-85 (published online in June 2015 ).
  10. ↑ L. von Berg et al .: Functional detection of botulinum neurotoxin serotypes A to F by monoclonal neoepitope-specific antibodies and suspension array technology . Scientific Reports , No. 9 (2019), s. 5531 doi : 10.1038 / s41598-019-41722-z
  11. ^ Guideline botulism of the German Society for Neurology . In: AWMF online (as of 10/2005)
  12. ^ William H. Sperber, Michael P. Doyle (Eds.): Compendium of the Microbiological Spoilage of Foods and Beverages. ISBN 978-1-4419-0825-4 , p. 313, section available from Google Books ; one of the two publishers is an employee of Cargill , one of the world's largest grain traders.
  13. ↑ Dave Chapeskie: Filtering Maple Sap. OMAFRA , archived from the original on April 7, 2006 ; Retrieved July 6, 2016 (Section Types of Microorganisms Found in Maple Sap ).
  14. ↑ M. Kuehnelt-Leddin, T. Trabi, M.Dunitz-Scheer, K.Burmucic, P.Scheer: Infantile botulism, cause, therapy, aftercare , German paediatrics, 2009-157: 911-913.
  15. ↑ Technical rule BVL L 06.00-26: 1988-12 Analysis of food; Detection of Clostridium botulinum and botulinum toxin in meat and meat products .
  16. ↑ Burkhard Schütze, LADR food analysis : Clostridium botulinum - Molecular biological detection of the toxin genes of food, PDF , Deutsche Lebensmittel-Rundschau , December 2015.
  17. ↑ Haim M. Solomon and Timothy Lilly, Jr .: Bacteriological Analytical Manual, Chapter 17: Clostridium botulinum . FDA , accessed July 6, 2016.