The role of a sequencing-based clinical intestinal screening test in patients at high-risk for Clostridium difficile and other pathogens: a case report

Hospitalization and antibiotic treatment can put patients at high risk for Clostridium difficile infection, where a disturbance of the gut microbiome allows for Clostridium difficile proliferation and associated symptoms, including mild, moderate, or severe diarrhea. Clostridium difficile infection is challenging to treat, often recurrent, and leads to almost 30,000 annual deaths in the USA alone. Here we present a case where SmartGut™, an at-home, self-administered sequencing-based clinical intestinal screening test, was used to identify the presence of Clostridium difficile in a patient with worsening diarrhea. Identification of this pathogen and subsequent treatment led to a significant improvement in symptoms.

The patient is a 29-year-old white woman with a history of severe irritable bowel syndrome with diarrhea, hemorrhoidectomy, and anal sphincterotomy complicated by a perianal fistula and perirectal abscesses that required extended courses of broad-spectrum antibiotics. In June 2016, she developed intermittent Clostridium difficile infections, which required continued antibiotic use. Months later she used an at-home, self-administered, intestinal microbial test, the first of which was negative for the presence of Clostridium difficile, but it detected the relative abundance of microbes associated with irritable bowel syndrome outside the healthy reference ranges. In the subsequent 2 months after the negative Clostridium difficile result, her gastrointestinal symptoms worsened dramatically. A second microbiome test resulted in a positive Clostridium difficile finding and continued abnormal microbial parameters, which led the treating physician to refer her to a gastroenterologist. Additional testing confirmed the presence of Clostridium difficile with a toxin-positive strain. She received treatment immediately and her gastrointestinal symptoms improved significantly over the next week.

This case report suggests that more frequent DNA testing for Clostridium difficile infections may be indicated in patients that are at high-risk for Clostridium difficile infection, especially for patients with irritable bowel syndrome, and those who undergo gastrointestinal surgery and/or an extended antibiotic treatment. This report also shows that such testing could be effectively performed using at-home, self-administered sequencing-based clinical intestinal microbial screening tests. Further research is needed to investigate whether the observations reported here extrapolate to a larger cohort of patients.