E. coli O157:H7
<p>E. coli strains can be classified by their O and H antigens.  
 </p>
<ul>
<li><b>O antigen</b> - defined serologically and determined by the repeating polysaccharide chains that are part of the lipopolysaccharide (LPS) embedded in the outer leaflet of the outer membrane</li>
<li><b>H antigen</b> - defined serologically by the antigenic specificity of the bacterial flagellum</li>
</ul>
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