El Tor biotype of Vibrio cholerae O1 differs from classical biotype in which of the following characteristics?

• A El Tor does not agglutinate chicken erythrocytes and is polymyxin B sensitive
• B Classical biotype is VP positive and El Tor is negative
• C Classical biotype causes more severe disease and higher case fatality rate than El Tor
• D El Tor produces Haemolysin, is VP positive, and is polymyxin B resistant ✓

Explanation

El Tor biotype is VP (Voges-Proskauer) positive, hemolyzes sheep RBCs (produces haemolysin), agglutinates chicken erythrocytes (Greig test positive), and is polymyxin B resistant. Classical biotype is VP negative, non-haemolytic, and polymyxin B sensitive. Classical biotype historically caused more severe disease, but altered El Tor strains now cause equally severe disease. The current 7th pandemic is caused by El Tor biotype.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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