Shigella dysenteriae

Shigella dysenteriae
	Dark-field microscopy revealing Shigella dysenteriae bacteria
Scientific classification
Domain:	Bacteria
Phylum:	Pseudomonadota
Class:	Gammaproteobacteria
Order:	Enterobacterales
Family:	Enterobacteriaceae
Genus:	Shigella
Species:	S. dysenteriae
Binomial name
	Shigella dysenteriae ; (Shiga 1897) ; Castellani & Chalmers 1919

Shigella dysenteriae is a species of the rod-shaped bacterial genus Shigella . ^[1] Shigella species can cause shigellosis ( bacillary dysentery ). Shigellae are Gram-negative , non-spore-forming , facultatively anaerobic , nonmotile bacteria. ^[2] S. dysenteriae has the ability to invade and replicate in various species of epithelial cells and enterocytes . ^[3]

Signs and symptoms [ edit ]

The most commonly observed signs associated with Shigella dysentery include colitis , malnutrition , rectal prolapse , tenesmus , reactive arthritis , and central nervous system problems. Further, S. dysenteriae is associated with the development of hemolytic-uremic syndrome , which includes anemia , thrombocytopenia , and kidney failure . If infected with S. dysenteriae , an individual will experience a severe case of shigellosis . ^[4] Mortality is higher with S. dysenteriae type 1. ^[3] Most cases of shigellosis are in developing countries. Shigellosis outbreaks in Asia, Latin America and Africa have had mortality rates of up to 20%. ^[4]

Diagnosis [ edit ]

Since the typical fecal specimen is not sterile, the use of selective plates is mandatory. XLD agar , DCA agar , or Hektoen enteric agar are inoculated; all give colorless colonies as the organism is not a lactose fermenter. Inoculation of a TSI slant shows an alkaline slant and acidic, but with no gas, or H
₂S production. Following incubation on SIM, the culture appears nonmotile with no H
₂S production. Addition of Kovac's reagent to the SIM tube following growth typically indicates no indole formation ( serotypes 2, 7, and 8 produce indole ^[5]). Mannitol tests yields negative results. ^[4] Ornithine Decarboxylase tests yield negative results. ^[4]

Treatment [ edit ]

Treatment for shigellosis, independent of the subspecies, requires an antibiotic . Commonly used antibiotics include ampicillin , ciprofloxacin , ceftriaxone , among others. Opioids should be avoided for treatment of Shigellosis . ^[3]

Epidemiology [ edit ]

Shigella infections may be contracted by a lack of monitoring of water and food quality, unsanitary cooking conditions and improper hygiene practices. ^[6] S. dysenteriae spreads through contaminated water and food, causes minor dysentery because of its Shiga toxin , but other species may also be dysentery agents. ^[7] S. dysenteriae releases an exotoxin that compromises the gut and central nervous system. ^[4] If acting as an enterotoxin , diarrhea will occur. When acting as a neurotoxin , severe cases of shigellosis are developed, inducing comas and meningismus . ^[4]

Contamination is often caused by bacteria on unwashed hands during food preparation, or soiled hands reaching the mouth. ^{[
citation needed
]}

References [ edit ]

^ Rodriguez, Margaret (2022). "16. Gram negative bacilli and coccobacilli: Enterobacteriaceae, Shigella" . Microbiology for Surgical Technologists (3rd ed.). Cengage. pp. 222?224. ISBN 978-0-357-62624-5 .
^ Hale, Thomas L.; Keusch, Gerald T. (1996). "Shigella: Structure, Classification, and Antigenic Types" . In Baron, Samuel (ed.). Medical microbiology (4 ed.). Galveston, Texas: University of Texas Medical Branch. ISBN 978-0-9631172-1-2 . Retrieved February 11, 2012 .
^ ^a ^b ^c Ryan, Kenneth James (2018). "Chapter 33: Enterobacteriaceae". Sherris Medical Microbiology (7th ed.). McGraw-Hill Professional Med/Tech.
^ ^a ^b ^c ^d ^e ^f Karen C. Carroll; Jeffery A. Hobden; Steve Miller; Stephen A. Morse; Timothy A. Mietzner; Barbara Detrick; Thomas G. Mitchell; James H. McKerrow; Judy A. Sakanari (2016). "Chapter 15: Enteric Gram-Negative Rods (Enterobacteriaceae)". Jawetz, Melnick, & Adelberg's Medical Microbiology (27 ed.). McGraw-Hill Professional Med/Tech.
^ Germani, Y.; Sansonetti, P.J. (2006). "Chapter 3.3.6: The Genus Shigella ". In Dworkin, M. (editor-in-chief) (ed.). The Prokaryotes: Proteobacteria: gamma subclass . Vol. 6 (3rd ed.). Springer. pp. 99?122. doi : 10.1007/0-387-30746-x_6 . ISBN 0-387-25496-X . {{ cite book }}: |editor1-first= has generic name ( help )
^ Justin L. Kaplan MD; Robert S. Porter MD (2018). Larry M. Bush,MD (ed.). Merck Manual Consumer Version .
^ Herold S; Karch H; Schmidt H (2004). "Shiga toxin-encoding bacteriophages?genomes in motion". International Journal of Medical Microbiology . 294 (2?3): 115?121. doi : 10.1016/j.ijmm.2004.06.023 . PMID 15493821 .

External links [ edit ]

Shigella dysenteriae at the NCBI Taxonomy Browser
Type strain of Shigella dysenteriae at BacDive, the Bacterial Diversity Metadatabase

This Enterobacterales article is a stub . You can help Wikipedia by expanding it .

[Rodriguez2022-1] Rodriguez, Margaret (2022). "16. Gram negative bacilli and coccobacilli: Enterobacteriaceae, Shigella" . Microbiology for Surgical Technologists (3rd ed.). Cengage. pp. 222?224. ISBN 978-0-357-62624-5 .

[Baron-2] Hale, Thomas L.; Keusch, Gerald T. (1996). "Shigella: Structure, Classification, and Antigenic Types" . In Baron, Samuel (ed.). Medical microbiology (4 ed.). Galveston, Texas: University of Texas Medical Branch. ISBN 978-0-9631172-1-2 . Retrieved February 11, 2012 .

[Sh33-3] Ryan, Kenneth James (2018). "Chapter 33: Enterobacteriaceae". Sherris Medical Microbiology (7th ed.). McGraw-Hill Professional Med/Tech.

[Jaw-4] ^ ^a ^b ^c ^d ^e ^f Karen C. Carroll; Jeffery A. Hobden; Steve Miller; Stephen A. Morse; Timothy A. Mietzner; Barbara Detrick; Thomas G. Mitchell; James H. McKerrow; Judy A. Sakanari (2016). "Chapter 15: Enteric Gram-Negative Rods (Enterobacteriaceae)". Jawetz, Melnick, & Adelberg's Medical Microbiology (27 ed.). McGraw-Hill Professional Med/Tech.

[5] Germani, Y.; Sansonetti, P.J. (2006). "Chapter 3.3.6: The Genus Shigella ". In Dworkin, M. (editor-in-chief) (ed.). The Prokaryotes: Proteobacteria: gamma subclass . Vol. 6 (3rd ed.). Springer. pp. 99?122. doi : 10.1007/0-387-30746-x_6 . ISBN 0-387-25496-X . {{ cite book }}: |editor1-first= has generic name ( help )

[6] Justin L. Kaplan MD; Robert S. Porter MD (2018). Larry M. Bush,MD (ed.). Merck Manual Consumer Version .

[7] Herold S; Karch H; Schmidt H (2004). "Shiga toxin-encoding bacteriophages?genomes in motion". International Journal of Medical Microbiology . 294 (2?3): 115?121. doi : 10.1016/j.ijmm.2004.06.023 . PMID 15493821 .

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