Shigella dysenteriae

Shigella dysenteriae
	Shigella dysenteriae
Systematics
Department :	Proteobacteria
Class :	Gammaproteobacteria
Order :	Enterobacterales
Family :	Enterobacteriaceae
Genre :	Shigella
Type :	Shigella dysenteriae
Scientific name
	Shigella dysenteriae
	( Shiga 1897) ; Castellani & Chalmers 1919

Shigella dysenteriae is a non-spore forming , gram-negative , rod-shaped, facultative anaerobic and immobile bacterium . It is named for the Japanese microbiologist Kiyoshi Shiga , who discovered the pathogen independently of and at the same time as the German hygienist Walter Kruse (1864–1943) in 1897, as well as diarrhea (dysentery), the main symptom of an infection. Genetically, morphologically and physiologically it is closely related to Escherichia coli .

Shigella dysenteriae is usually pathogenic, primarily for humans, and mainly causes abdominal pain and diarrheal diseases . The most common route of infection is ingestion through contaminated food , especially drinking water contaminated with faeces .

properties

Morphology and physiology

Shigella dysenteriae is a gram-negative and facultatively anaerobic bacterium. The cells are rod-shaped. Shigella dysenteriae does not form spores and is closely related to Escherichia coli . Both species belong to the enterobacteria family , to which the Yersinia , Klebsiae and the genus Citrobacter also belong, and are morphologically and physiologically very similar. They can be distinguished by some biochemical tests. In contrast to Escherichia coli , Shigella dysenteriae can not break down lactose , and Shigella does not have a decarboxylase to break down lysine . The two types can also be distinguished using serological methods.

proof

The clinical detection of Shigella dysenteriae is carried out by microscopic examination of a stool sample and enrichment culture with selective nutrient media . Identification is possible using biochemical tests or specific antibodies , as can detection using the polymerase chain reaction (PCR) and subsequent hybridization with specific DNA probes. Shigella can survive on toilet seats for over 14 days. However, a stool sample should be processed within three hours. A rectal swab is therefore an alternative.

Pathogenicity

Ten to 200 germs are sufficient for an infection with Shigella dysenteriae , which is also known as bacterial dysentery or shigellosis . The main symptoms are cramp-like abdominal pain , sudden high fever and diarrhea , and occasionally vomiting . The Shigella enterotoxins produced by the bacteria are primarily responsible for these symptoms . Shiga toxin , also formed by some enterohaemorrhagic Escherichia coli , also means that the excreted feces contain blood in around 70 percent of cases . Haemolytic uremic syndrome can therefore occur in children in particular . The incubation period until the first symptoms appear is usually one to two days, and the duration of an untreated infection is five to seven days. Epidemics can occur in regions with poor hygiene and inadequate medical care. The lethality is then around five to 15 percent.

Infection often requires treatment, particularly in children and the elderly. An antibiotic treatment is usually with ciprofloxacin and ampicillin . In the case of severe fluid loss ( dehydration ) due to diarrhea, fluids containing electrolytes are also administered orally or intravenously . For prevention , compliance with the relevant hygiene regulations and the proper preparation and storage of food are essential.

The suspicion of an infection with Shigella dysenteriae as well as confirmed cases of illness, deaths and permanent eliminators must be reported in Germany according to the Infection Protection Act.

literature

SK Niyogi: Shigellosis. In: Journal of Microbiology. 43 (2) / 2005. Microbiological Society Of Korea, pp. 133-143, ISSN 1225-8873
P. Shears: Shigella infections. In: Annals of Tropical Medicine and Parasitology. 90 (2 )/1996. Carfax, pp. 105-114, ISSN 0003-4983
Samuel Baron: Medical Microbiology. 4th edition. The University of Texas Medical Branch at Galveston, 1996, ISBN 0-9631172-1-1

Web links

Shigellosis. Robert Koch Institute
Shigella spp. US FDA / CFSAN Foodborne Pathogenic Microorganisms and Natural Toxins Handbook (English)

Individual evidence

↑ Ortrun Riha : Kruse, Walter. In: Werner E. Gerabek , Bernhard D. Haage, Gundolf Keil , Wolfgang Wegner (eds.): Enzyklopädie Medizingeschichte. De Gruyter, Berlin / New York 2005, ISBN 3-11-015714-4 , p. 812.

↑ aok.de ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. AOK to Shigella.@1@ 2Template: Dead Link / www.aok.de

↑ Lois J. Paradise, Mauro Bendinelli, Herman Friedman: Enteric infections and immunity. Springer, 1996, ISBN 0-306-45242-1 p. 79 ff.

[1] Ortrun Riha : Kruse, Walter. In: Werner E. Gerabek , Bernhard D. Haage, Gundolf Keil , Wolfgang Wegner (eds.): Enzyklopädie Medizingeschichte. De Gruyter, Berlin / New York 2005, ISBN 3-11-015714-4 , p. 812.