Shigella
Photomicrograph of Shigella sp. in a stool specimen
Scientific classification
Kingdom: Bacteria Phylum: Proteobacteria Class: Gamma Proteobacteria Order: Enterobacteriales Family: Enterobacteriaceae Genus: Shigella Castellani & Chalmers 1919
Species
S. boydii Image File history File links Shigella_stool. ... A micrograph is a photograph or similar image taken through a microscope or similar device to show a magnified image of an item. ... Scientific classification or biological classification is a method by which biologists group and categorize species of organisms. ... Phyla/Divisions Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Omnibacteria Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular, bacterium) are a major group of living organisms. ... Orders Alpha Proteobacteria    Caulobacterales - e. ... Orders Alpha Proteobacteria    Caulobacterales - e. ... Genera see text The Enterobacteriaceae are a large family of bacteria, including many of the more familiar pathogens, such as Salmonella and Escherichia coli. ... Genera see text The Enterobacteriaceae are a large family of bacteria, including many of the more familiar pathogens, such as Salmonella and Escherichia coli. ... Binomial name Shigella boydii Ewing 1949 Shigella boydii is a Gram-negative bacteria of the genus Shigella. ... S. dysenteriae This article needs to be cleaned up to conform to a higher standard of quality. ... S. flexneri Shigella Flexneri can cause diarrhea in humans. ... S. sonnei

This article is about the bacteria. For the disease, see shigellosis

Shigella is a genus of Gram-negative, non-motile, non-spore forming rod-shaped bacteria closely related to Escherichia coli and Salmonella. The causative agent of human shigellosis, Shigella also cause disease in other primates, but not in other mammals.^[1] For other uses of the word, please see Genus (disambiguation). ... Bacteria that are Gram-negative are not stained dark blue or violet by Gram staining, in contrast to Gram-positive bacteria. ... Motility is a biological term which refers to the ability to move spontaneously and independently. ... An endospore is a dormant, tough, non-reproductive structure produced by a small number of bacteria from the Firmicute family. ... Phyla/Divisions Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Omnibacteria Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular, bacterium) are a major group of living organisms. ... E. coli redirects here. ... Species Salmonella bongori Salmonella enterica Salmonella arizonae Salmonella enteritidis Salmonella typhi Salmonella typhimurium Salmonella is a genus of rod-shaped Gram-negative enterobacteria that causes typhoid fever, paratyphoid fever, and foodborne illness. ... Families 15, See classification A primate (L. primus, first) is any member of the biological order Primates, the group that contains all the species commonly related to the lemurs, monkeys, and apes, with the latter category including humans. ...

Classification

Shigella species are classified by four serogroups:

• Serogroup A: S. dysenteriae (12 serotypes)
• Serogroup B: S. flexneri (6 serotypes)
• Serogroup C: S. boydii (23 serotypes)
• Serogroup D: S. sonnei (1 serotype)

Group A–C are physiologically similar; S. sonnei (group D) can be differentiated on the basis of biochemical metabolism assays.^[2] This article needs to be cleaned up to conform to a higher standard of quality. ... Serotypes refer to a group of related microorganisms or viruses distinguished by responses to different antigens. ... Shigella Flexneri can cause diarrhea in humans. ... Binomial name Shigella boydii Ewing 1949 Shigella boydii is a Gram-negative bacteria of the genus Shigella. ...

Pathogenesis

Shigella infection is typically via ingestion (fecal–oral contamination); depending on age and condition of the host as few as ten bacterial cells can be enough to cause an infection. Shigella cause dysentery that results in the destruction of the epithelial cells of the intestinal mucosa in the cecum and rectum. Some strains produce enterotoxin and Shiga toxin, similar to the verotoxin of E. coli O157:H7.^[3] Dysentery (formerly known as flux or the bloody flux) is the term for tenesmus (painful straining to pass stool), cramping, and frequent, small-volume severe diarrhea associated with blood in the feces. ... The cecum or caecum (from the Latin caecus meaning blind) is a pouch connected to the ascending colon of the large intestine and the ileum. ... The rectum (from the Latin rectum intestinum, meaning straight intestine) is the final straight portion of the large intestine in some mammals, and the gut in others, terminating in the anus. ... This page is a candidate to be moved to Wiktionary. ... Shiga toxins are a family of related toxins with two major groups, Stx1 and Stx2, whose genes are considered to be part of the genome of lambdoid prophages. ... Escherichia coli O157:H7 is an emerging cause of foodborne illness. ...

Shigella invade the host through small intestine epithelial cells. Using a a Type III secretion system acting as a biological syringe, the bacterium injects Ipa protein into cell, triggering bacterial invasion, and the subsequently lysis of vacuolar membranes. It utilizes a mechanism for its motility by which its IpaC triggers actin polymerization in the host cell in a "rocket" propulsion fashion for cell-to-cell spread.

The most common symptoms are diarrhea, fever, nausea, vomiting, stomach cramps, and straining to have a bowel movement. The stool may contain blood, mucus, or pus (e.g. dysentery). In rare cases, young children may have seizures. Symptoms can take as long as a week to show up, but most often begin two to four days after ingestion. Symptoms usually last for several days, but can last for weeks.

Severe dysentery can be treated with ampicillin, TMP-SMX, or fluoroquinolones such as ciprofloxacin. Ampicillin is a beta-lactam antibiotic that has been used extensively to treat bacterial infections since 1961. ... Co-trimoxazole is a bacteriostatic antibiotic combination of trimethoprim and sulfamethoxazole, in the ratio of 1 to 5, used in the treatment of a variety of bacterial infections. ... Quinolones and fluoroquinolones form a group of broad-spectrum antibiotics. ... Ciprofloxacin is the generic international name for the synthetic antibiotic manufactured and sold by Bayer Pharmaceutical under the brand names Cipro and Ciproxin (and other brand names in other markets, e. ...

External links

• Genome information is available from the NIAID Enteropathogen Resource Integration Center (ERIC)

References