Shigella has the lowest infectious dose among bacterial enteric pathogens. Approximately how many organisms are required to cause infection via the fecal-oral route?

• A 10^8-10^9 organisms
• B 10^5-10^6 organisms
• C 10^3-10^4 organisms
• D 10-100 organisms ✓

Explanation

Shigella requires only 10-100 organisms to cause infection, the lowest infectious dose of any bacterial enteric pathogen, which explains its efficient person-to-person transmission and epidemic spread in settings with poor hygiene. By comparison, V. cholerae requires 10^8, ETEC 10^6-10^8, and Salmonella 10^4-10^6 organisms.

Reference: Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases, 9th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.