Researchers tested 220 patients who showed no symptoms of C. diff infection when they were admitted between July 2017 and March 2018. Perirectal swabs were completed within 24 hours of admission, and the patients were followed for six months. Upon admission, 21 patients were identified as carriers.

Within approximately six months, 38% percent of the asymptomatic carriers had developed full-blown C. diff infection — compared to just 2% of the noncarriers.

The study raises difficult questions, not the least of which is, if you seek information are you compelled to act on it? Clearly these colonized patients are at some risk themselves and may serve as a reservoir for transmission to other patients. On the other hand, there is no clear path to decolonization, and putting more patients in contact isolation has adverse effects of its own.

The lead author of the study, Sarah Baron, MD, MS, director of inpatient quality improvement at Montefiore Health System in New York City, spoke about the implications in an interview with Hospital Infection Control & Prevention.

HIC: You show that asymptomatic C. diff carriers can go on to develop active disease after admission. If screening is done and this colonization state is known, what are some of the options and implications for infection prevention?

Baron: I think for now we have a few ways to think about this. First of all, if screening was performed and we knew the colonization state of all patients, we could more carefully protect those patients who were not carriers. We could intensify our cleaning efforts to reduce spread, modify our isolation protocols, and educate the families. Infection prevention would carry some of the heaviest burden.

For the population who are carriers, though — the patients who went on to have symptomatic C. difficile almost 40% of the time in our study — we really could tailor our treatment with even more antimicrobial stewardship and potentially prophylactic treatment for high-risk patients.

In general, the knowledge that we would gain by identifying carriers might be an amazing opportunity to protect all of our patients, not only the carriers, from symptomatic infection.

HIC: You note that the infection preventionists would bear a fair portion of the burden. What are the pros and cons of putting these patients in contact isolation?

Baron: There are huge downsides to putting more patients in contact isolation, many of which I experience myself as a hospitalist caring for patients. The time and effort that it takes to appropriately put on personal protective equipment means that, amongst other things, patients get fewer visits or care from their care teams.

We have seen this in multiple studies, and it truly can lead to suboptimal patient care, even as we all are trying to keep everyone safe. The question that many institutions are grappling with is how to minimize those downsides while maximizing the protection that isolation provides.

HIC: Are there decolonization options for C. diff carriers?  

Baron: As of now, I do not know of any decolonization options, although we may be able to prevent full symptomatic C. difficile infection, in some high-risk populations at least, with prophylactic antibiotics.

HIC: Are you concerned that identifying colonized patients could encourage treatment or antibiotic use that may exacerbate their condition and lead to full-blown C. diff?

Baron: Absolutely. This was one of the concerns even performing our study, which is why we did not notify providers that their patients were carriers — unless and until the providers requested C. diff testing. Alongside the ongoing research on C. diff prophylaxis, treatment, and prevention, we will need some pragmatic research on educating clinicians to not reflexively treat and isolate C. diff carriers as if they had symptomatic disease. As a physician working in the hospital, I know that this message will take time to permeate. I, myself, would have had a difficult time not treating a positive C. diff test result before I started working in this area.

HIC: On the other hand, you note that knowing this colonized state enables clinicians to avoid using antibiotics known to disrupt the microbiome and set up C. diff infection.  

Baron: Yes. One of the hallmarks of successful antimicrobial stewardship programs is the decrease in use of antibiotics, which have been associated most strongly with the development of C. diff. This work continues, of course, but has become more and more nuanced with time.

Unfortunately, avoiding antibiotics is very difficult, as some of the antibiotics that we use to treat C. diff infections have been implicated in leading to more C. difficile infections — a tricky paradox. While all of us rely heavily on our colleagues in antimicrobial stewardship, I know that there also is work looking at innovative solutions to these issues, from more selective anti-C. diff antibiotics to oral beta-lactamases, which effectively might degrade any of our intravenous antibiotics that make it into the gastrointestinal tract and protect the microbiome. Screening for C. difficile carriage is one potentially useful step in our efforts towards C. difficile prevention, although certainly not the only option available.

REFERENCE

1. Baron S, Ostrowsky B, Nori P, et al. Screening of Clostridioides difficile carriers in an urban academic medical center: Understanding implications of disease. Infect Control Hosp Epidemiol 2019; Dec. 11. doi:10.1017/ice.2019.309. [Online ahead of print].