The Role of a Sequencing-based Clinical Intestinal Screening Test in Patients at High-risk for Clostridium Difficile and Other Pathogens

Discussion and Conclusions

The patient had multiple risk factors for C. difficile colonization and overgrowth, such as several out-patient visits, hospitalizations, and previous GI surgery.^[46] In this case, it is particularly important to note that repeat administration of combination and/or long-term broad-spectrum antibiotics may have contributed to changes in the patient's intestinal microbiome, potentially contributing to C. difficile proliferation. During treatment with antibiotics, bacterial organisms that are susceptible to the antibiotics decrease in abundance or disappear, which potentially generates a microenvironment that enables C. difficile to thrive and increase in relative abundance, which could lead to the development of CDI.^[47–49] Hence, it is recommended to prescribe antibiotics prudently. An example of a successful antibiotic stewardship intervention reducing CDIs in Scotland was avoiding the use of "4C" antibiotics: fluoroquinolones (for example, ciprofloxacin), clindamycin, co-amoxiclav, and third-generation cephalosporins, and using narrow-spectrum antibiotics instead (for example, fidaxomicin).^[48] Hence, reported new IBS treatment concepts involving the use of antibiotics need attention.^[50]

Importantly, this case study suggests that in high-risk populations, such as those repeatedly treated with antibiotics, there may be a need for more frequent and convenient testing for C. difficile and possibly for other GI pathogens as well. It makes sense that a self-administered, at-home, non-invasive test is an ideal adjunct solution for regular monitoring between scheduled appointments, particularly in patients who are already burdened by multiple visits to their health care providers or even by hospitalizations. Patients with known risk factors for CDI such as immunodeficiency, cystic fibrosis, and diabetes, or prolonged administration of antibiotics, proton pump inhibitors, and antidiarrheal medication^[46] may need to be screened more often and may benefit from at-home testing.

Further investigation is greatly needed to understand the potential connection between the human intestinal microbiome, IBS, and the presence of C. difficile. The role of C. difficile in IBS and co-occurrence rates in particular would also benefit from further research. It remains to be determined if incomplete treatment of CDI might be associated with the development of IBS, or if ongoing IBS might increase the risk of acquiring C. difficile. Current clinical outcomes analyses using data from our uBiome citizen science cohort will further illuminate whether individuals diagnosed as having IBS have higher carriage rates of C. difficile, a finding previously reported in other studies.^[44] Disturbance of the gut microbiome may therefore predispose patients with IBS to CDI and subsequent exacerbation of existing IBS symptoms due to the pathogen's toxigenic nature.^[43]

While our product (that is, SmartGut™) is not intended in any way to replace standard of care or to function as a diagnostic tool for acute infection, the use of an at-home clinical microbial screening test for pathogenic and commensal bacteria associated with chronic conditions is a minimally invasive testing option that may provide clinicians and patients with unique information that could positively impact time to treatment, as well as improve patient outcomes.

J Med Case Reports. 2019;13(9) © 2019 BioMed Central, Ltd.