Assessing the Relationship Between C-diff Risk and Antibiotic Exposure

With surging COVID-19 cases, an ongoing H5N1 outbreak, and a global health emergency related to mpox, we’ve got a number of infectious diseases challenges to face. In truth, that’s just the tip of the iceberg. Of these public health threats, there are some that are frequently neglected, healthcare-associated infections, antimicrobial resistance, and Clostridioides difficile (C difficile).

C difficile in particular is one that has challenged healthcare infection prevention efforts and can be deeply impactful for patients. The Centers for Disease Control and Prevention (CDC) recently reported that in 2022, the incidence rates of C difficile infection (CDI) increased with age and rates were higher in women. Moreover, there were 116 cases per 100,000 persons reported in surveillance sites, with 56% of cases having used antibiotics in the 12 weeks prior to infection.¹

As the leading cause of healthcare-associated diarrhea globally and causes over 225,000 hospitalizations within the United States alone, CDI is a significant public health burden. Moreover, CDI represents an important aspect of antimicrobial stewardship given that recent exposure to certain classes of antibiotics has shown to increase risk.

As we work to understand the risk factors and transmission dynamics for CDI, so much points to the significance of recent antibiotic use and/or presence in a healthcare facility. How does transmission work in relation to exposure to high CDI-risk antibiotics and in what way is colonization impacted? In light of these variables, a new study has been published in PLoS One regarding the underlying mechanisms for assessing relative risk of CDI in those hospitalized patients with antibiotic exposure.²

Using a deterministic model to understand the relationship and risk ratio of CDI in those patients with and without antibiotic exposure, the researchers sought to then calculate the sensitivity of potential antimicrobial stewardship intervention impacts. The goal was really to understand how acquiring C difficile (and progression of disease) is impacted by antimicrobial exposure. The authors delved into transmission dynamic models comparing antibiotic exposure outcomes to risk, noting how patients can transition from elevated to no elevated risk, but also a compartment model in which patients were either susceptible, colonized, or infected.

The authors found that, “the impact of 2 antibiotic stewardship interventions on facility acquisition and progression from colonization is as expected, by decreasing the overall antibiotic prescribing rate both the rate of acquisition and the rate of progression to CDI decrease.” Interestingly, when exploring the potential impact of shortening the duration that high-risk antibiotics were given, they found that “that the facility-onset acquisition rate and the facility-onset progression are both increased” and that when shifting prescriptions from high to low risk antibiotic classes, the impact “decreases both the rate of facility-onset infections and colonizations.”

Ultimately, this study points to the need for additional research and data to harness modeling power as we learn more about the role of stewardship programs and CDI within hospitalized patients. The authors note that the effects of stewardship interventions are “sensitive to their assumed values,” drawing attention to the impact of assumptions in these models and our overall understanding of these dynamics.

In short, it is vital that we invest more resources into understanding CDI infections, transmission, and the role of antimicrobial stewardship interventions.

References

1.Clostridioides difficile Infection (CDI) Surveillance. CDC. 2024. June 26, 2024. Accessed September 11, 2024.
https://www.cdc.gov/healthcare-associated-infections/php/haic-eip/cdiff.html

2.Mitchell C, Keegan LT, Le TTT, et al. Importance of underlying mechanisms for interpreting relative risk of Clostridioides difficile infection among antibiotic-exposed patients in healthcare facilities. PLoS One. 2024;19(8):e0306622. Published 2024 Aug 8. doi:10.1371/journal.pone.0306622