What is the role of enterotoxins in pathogenic strains of E. coli?

• A. They contribute to weight loss
• B. They stimulate fluid secretion contributing to diarrheal disease
• C. They enhance antibiotic resistance
• D. They trigger immune responses

Answer: (B)

Enterotoxins produced by pathogenic strains of E. coli play a crucial role in the development of diarrheal disease by stimulating fluid secretion in the intestinal lumen. These toxins, such as heat-labile enterotoxin (LT) and heat-stable enterotoxin (ST), act on intestinal epithelial cells and increase the levels of cyclic AMP or cyclic GMP, leading to enhanced secretion of electrolytes and water into the intestines. This physiological change results in profuse watery diarrhea, a hallmark symptom of infections caused by enterotoxigenic E. coli (ETEC), which is often associated with traveler's diarrhea.

The other choices are not accurate in the context of enterotoxin function. While enterotoxins do impact fluid secretion, they do not contribute to weight loss directly, enhance antibiotic resistance, or primarily trigger immune responses. Instead, the result of their action is often a rapid loss of body fluids, which can lead to dehydration and its associated complications, rather than other effects like those proposed in the other options.