X-ray diffraction technology is used to analyze the drug efflux pump, ST50, form S. Typhi. The drug efflux mechanism for multiple drug resistant (MDR) S. Typhithe potential location for antigen of market-based typhoid detection reagent are understood through this ST50 structure. It could help develop the more effective typhoid detection reagentthe new antibiotics against MDR S. Typhi.

1. The protocol for the preparation of massive, high-purity drug efflux pumps, ST50, from S. Typhi are set up. 
2. The X-ray structure of ST50 is determined. 
3. Possible antigenic active regions of ST50  for patients antibody detection are determined. 
4. The 3D structure of the active region of ST50 for drug efflux is determined.

1. It can be applied to researchdevelop a new generation of typhoid detection reagent with better effect than TYPHIDOT.  
2. The new antibiotics against drug-resistant S. Typhi can be developed using X-ray protein structure-based drug designdevelopment technology.