Shigella spp.

Shigella spp. are facultatively anaerobic Gram-negative rod-shaped bacteria, belonging to the Enterobacteriaceae family. Representatives of the genus include Shigella flexneri, Shigella sonnei, Shigella dysenteriae and Shigella boydii. The pathogens are closely related to Escherichia coli [1][2][3].

Shigella spp. are one of the leading causes of bacterial gastroenteritis worldwide. Diseases caused by these pathogens commonly occur in children aged 1 to 4 years and are particularly predominant in less developed countries. In the vast majority of cases, the pathogens S. flexneri, S. sonnei and S. dysenteriae are present [2][4].

The clinical pictures include:

  • Diarrhea

  • Dysentery (Shigella dysentery, inflammatory diarrhea with blood in the stool)

The infectious dose of 10–100 organisms is very low compared to other pathogens that cause diarrheal diseases [5]. In terms of endoscopy, acute inflammatory bowel diseases such as shigellosis are sometimes difficult to differentiate from other clinical presentations such as ulcerative colitis [6].

Shigella spp. are found almost exclusively in humans and other primates. Only rarely have the pathogens been found isolated in samples taken from wild animals, such as wild birds, amoebas and insects [2][3].

Relevance of pathogen in transmission in endoscopy

  • Gastroenterology: Low

  • Pulmonology: Not relevant

  • Ear, nose, and throat: Not relevant

  • Urology: Not relevant

Relevance for endoscope surveillance

  • High concern organism

Transmission route

Transmission occurs mainly through close contact with infected/unwell people and through contaminated objects and food, including contaminated water [2][3].

Resistance to antibiotics

Shigella spp. belongs to the group of multidrug-resistant Gram-negative bacteria (MRGN) and exhibits resistance in particular to beta-lactam antibiotics such as fluoroquinolones and third-generation cephalosporins. Shigella spp. numbers among the ESBL (extended-spectrum beta-lactamase)-forming bacteria [3][7].

Sources and further readings

  1. Gries, O./Ly, T. Infektologie – Kompendium humanpathogener Infektionskrankheiten und Erreger [Infectious Diseases – Compendium of Human-pathogenic Infectious Diseases and Pathogens], Springer-Verlag Berlin Heidelberg 2019.

  2. Lampel, K. et al. A Brief History of Shigella. American Society of Microbiology Journals, EcoSal Plus. 2018; 8 (1): 1–42.

  3. Robert Koch Institute. Ratgeber Shigellose [Shigellosis guide]. Status as on 02/03/2021. https://bit.ly/3lANCKQ. Accessed on 03.23.2023.

  4. Nikfar R et al. A Study of prevalence of Shigella species and antimicrobial resistance patterns in paediatric medical center in Ahvaz, Iran. Iranian Journal of Microbiology. 2017; 9(5):277–282.

  5. Bellido-Blasco JB, Arnedo-Pena A. Epidemiology of Infectious Diarrhea. Encyclopedia of Environmental Health. 2011; 569–581.

  6. Annesea, V. et al. European evidence based consensus for endoscopy in inflammatory bowel disease. Journal of Crohn’s and Colitis. 2013; 7: 982–1018.

  7. Ranjbar, R., Farahani, A. Shigella: Antibiotic-Resistance Mechanisms and New Horizons for Treatment. Infection and Drug Resistance. 2019; 12: 3137–3167.