Shigella spp

From Dog
Shigella dysenteriae under electron microscopy[1]

Shigella spp are a Gram-negative, anaerobic zoonotic proteobacteria closely related to Escherichia coli and Salmonella spp.

Shigella species are human pathogens capable of colonizing the intestinal epithelium by exploiting epithelial cell functions and circumventing the host innate immune response[2]. The most common mode of transmission of this bacteria is the fecal-oral route. Outbreaks in humans occur via foods contaminated by hands or feces of carrier individuals. Insects, particularly flies, can also play a role as mechanical vectors. In highly endemic areas, dogs may shed Shigella temporarily.

Although only considered pathogenic to humans and primates, it has been identified in the intestinal microbiota of dogs.

Species which are pathogenic to dogs include:

  • Shigella dysenteriae
  • Shigella flexneri
  • Shigella boydii
  • Shigella sonnei

Clinical signs are rare in dogs, with intermittent or transient diarrhea common.

Definitive diagnosis depends on isolation of the etiologic agent by culture of fecal material on selective media. Serologic identification and typing are important from the epidemiologic viewpoint[3].

Treatment in dogs is not usually required, but the current antimicrobial treatment of choice is trimethoprim-sulfamethoxazole.

Control methods are critical at minimizing spread of the bacterium, especially disposal of human waste and provision for potable water.


  1. Microbiology Book
  2. Sansonetti PJ (2001) Microbes and microbial toxins: paradigms for microbial-mucosal interactions III. Shigellosis: from symptoms to molecular pathogenesis. Am J Physiol Gastrointest Liver Physiol 280:G319–G323
  3. PH Source