15842
Serological screening of 55 strains of P . shigelloides with the use of serum against identified core oligosaccharide conjugated with bovine serum albumin ( BSA ) indicated the presence of similar structures in the LPS core region of 28 O - serotypes .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
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