The El Tor biotype of Vibrio cholerae O1, which currently causes most cholera outbreaks worldwide, differs from the classical biotype in that it:

• A Produces a more severe watery diarrhea with higher case fatality
• B Is Voges-Proskauer (VP) positive and survives longer in the environment ✓
• C Is sensitive to Polymyxin B unlike the classical biotype
• D Does not produce cholera toxin (CT) unlike the classical biotype

Explanation

El Tor biotype is VP (Voges-Proskauer) positive due to acetoin production, while classical biotype is VP negative. El Tor biotype also survives longer in the environment, is resistant to Polymyxin B (not sensitive), produces hemagglutinin, and tends to cause milder disease with a lower case fatality rate (CFR) than classical. Both biotypes produce cholera toxin. The higher environmental persistence of El Tor explains its pandemic dominance (7th pandemic). El Tor strains producing classical CT (altered El Tor) now cause more severe disease.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.