Vibrio cholerae acquires the genes encoding cholera toxin (ctxAB) through horizontal gene transfer. The filamentous bacteriophage that carries ctxAB and integrates into the V. cholerae chromosome is called:

• A CTXphi phage ✓
• B Toxin-converting phage lambda
• C RS1 satellite phage
• D VPI-1 phage

Explanation

CTXphi is the filamentous filamentous phage that carries the ctxAB genes encoding cholera toxin. It integrates into the V. cholerae chromosome at specific attachment sites. RS1 is a satellite phage that flanks CTXphi elements and aids in phage production. VPI-1 (Vibrio pathogenicity island 1) encodes the toxin-coregulated pilus (TCP) which serves as the receptor for CTXphi, but VPI-1 itself is not a phage.

Reference: Jawetz, Melnick, & Adelberg's Medical Microbiology, 28th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.