This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
Adhesin is useful in- 
Select and explain. 
A. Motility, B. Bacterial attachment, C. Toxigenicity, D. Bacterial division
B: Bacterial attachment
Answer: B: Bacterial attachment 
Explanation: Bacterial adhesins 

Specific adhesion to host tissue cells is an essential virulence factor of most bacterial pathogens. 
The fundamental process that determines bacterial attachment to host tissue surfaces is mediated by microbial adhesins.
Most fimbriae of gram-negative bacteria function as adhesins, but in many cases, it is a minor subunit protein at the tip of the fimbriae that is actual adhesin.
In grain-positive bacteria, a protein or polysaccharide surface layer serves as the specific adhesin.