SECTION 3.3 Gamma Subclass

The Prokaryotes

pp 99-122

The Genus Shigella

  • Yves Germani
  • , Philippe J. Sansonetti

Introduction

Shigella is a Gram-negative, nonmotile, nonsporeforming, non-lactose-fermenting, facultatively anaerobic bacillus belonging to the family Enterobacteriaceae. It causes bacillary dysentery or shigellosis, as do enteroinvasive Escherichia coli strains (EIEC). The disease naturally occurs only in humans and primates. It is characterized, in its classical form, by acute colonic and rectal mucosal inflammation that leads to the triad of the dysenteric syndrome: fever, intestinal cramps, and passage of blood and mucus in diarrheal stools. Shigella dysenteriae 1 was the first of the four Shigella species to be described in 1898 by the Japanese microbiologist K. Shiga, thus the name of Shiga bacillus. The four species share several major characteristics such as lack of motility, optimal growth at 37°C, oxidase-negative character, and lack of growth in synthetic media containing salts and a simple carbon source, unless glucose and nicotinic acid are added. Some isolates may require ...

This is an excerpt from the content