Enteropathogenic <scp> <i>Escherichia coli</i> </scp> ( <scp>EPEC</scp> ) Causes Chronic Diarrhea and Hyponatremia in an Adult

Enteropathogenic <i>Escherichia coli</i> (EPEC) is frequently identified on gastrointestinal pathogen multiplex polymerase chain reaction testing. However, it is unclear whether EPEC causes diarrhea in adults. We describe the case of a 48-year-old man living in the United States who presented with 6 weeks of large-volume watery diarrhea and significant hyponatremia refractory to hypertonic saline and fluid restriction, who was found to have EPEC. Ciprofloxacin was initiated, resulting in the resolution of both diarrhea and hyponatremia. This case demonstrates that EPEC can be pathogenic in adults and can be associated with significant hyponatremia.