Reports of disease caused by enteropathogenic e. coli and its relative, salmonella, usually include a description of the responsible serotype. for example, in 1993, hundreds of infections from shiga-toxin-producing e. coli resulted from undercooked hamburgers sold by jack-in-the-box restaurants. the outbreak was caused by the now-infamous e. coli strain o157: h7. the "o" in this designation refers to an antigen on which of the following molecules?
a. osmoregulatory proteins
b. capsular oligosaccharide
c. lipopolysaccharide
d. outer membrane lipoprotein
e. outer membrane porins