Veterinary bacteriology: information about important bacteria
|Etymology:||Genus name: named after the Japanese bacteriologist K. Shiga, who first (1896) discovered the bacterium, which causes dysentery|
Species name: of dysentery
|Significance:||Outbreaks of human dysentery are not common in Sweden (about 5 cases per year) and the disease occurs primarely in developing countries. However, a comparatively big outbreak (45 persons) has recently (May-June, 2009) occured in Sweden. The suspected infection source was contaminated imported vegetables.
|Type Strain:||ATCC 13313 = NCTC 4837.|
|Micromorphology:||Small (0.4-0.6 x 1-3 µm), non-motile rods.|
|Gram +/Gram -:||G-|
|Other Enzymes:||Esculinase -, tryptophanase V (serotype 1: -, serotype 2: +), urease -.|
|Biochemical Tests:||Citrate -, methyl red +, Voges-Proskauer -.|
|Fermentation of carbohydrates:||
Glucose (gas) -, melibios -, xylos -.
|Disease:||Shigellosis or bacillary dysentery.
|Hosts:||Primates (including humans).|
|Clinical Picture:||Fever, vomitting, abdominal pain and mucoid bloody diarrhea.|
|Virulence Factors:||The shigatoxin (AB5), which is coded by the stx gene and which is composed of two different subunits (A and B). B is a pentamer, which makes it possible for the toxin to bind to a specific glycolipid on the cellsurface. Then the A subunit can enter the cell, where it will be cleaved to an active exonuclease (A1). A1 inhibits protein biosynthesis by removing an adenosine residue from the 28S rRNA. This will in turn result in damages on epithelial cells.|
|16S rRNA Seq.:|
||Four species have been described within the genus Shigella. These species and Escherichia coli are all very closely related and can phylogenetically be regarded as the same species. In spite of that fact, they have been taxonomically arranged into two different genera.|
|Legislation:||Human dysentery is in Sweden classified as a notifiable disease and it is compulsary to report it to the Public Health Agency of Sweden. S. dysenteriae belongs to category B as a potential biological weapon according to NIAID.|
|Comment:||Escherichia coli of type VTEC (verotoxin producing E. coli) has Shiga like toxins.|
|The taxonomy of chlamydias|
Species within the family Chlamydiaceae were previously divided into two genera Chlamydia and Chlamydophila. However, the differences between these two genera were not that great and many research groups have not accepted this division. Therefore, the genus Chlamydophila has been returned to the genus Chlamydia and this change has now been incorporated in VetBactPublished 2023-03-15. Read more...
|New names of bacterial phyla|
The taxonomic category phylum was previously not regulated by the International Code of Nomenclature of Prokaryotes (ICNP), but now this has changed and it was decided to revise the names of bacterial phyla. All phyla must be written in italics (which has been done on VetBact also before) and have the ending -ota.Published 2023-03-01. Read more...