Enteropathogenic E. coli (EPEC) is a major cause of infantile diarrhea in developing countries. The hallmark 'attaching and effacing' (A/E) lesion on intestinal epithelium is mediated by which specific outer membrane protein that binds to the translocated intimin receptor (Tir) injected by the Type III secretion system?

• A Bundle-forming pilus (BfpA)
• B Intimin ✓
• C EspA filament protein
• D Flagellin (FliC)

Explanation

Intimin is the outer membrane adhesin of EPEC that binds to Tir, which is injected into the host cell via the Type III secretion system. This intimate attachment triggers actin pedestal formation and the B/E lesion. Bundle-forming pilus mediates initial microcolonial adherence but not the intimate attachment. EspA forms the filamentous needle conduit. Flagellin is unrelated to B/E lesion formation.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.