Blog | Friday, May 5, 2017

Wherein I reveal the top 3 approaches for preventing C. difficile disease


1. Antibiotic stewardship
2. Antibiotic stewardship
3. Antibiotic stewardship

I've listed these in order of importance. Supporting evidence is accumulating, including three recent papers that I found very interesting:

Dingle, et al. Lancet Infect Dis 2017. This observational study from Oxfordshire, UK combined overall Clostridium difficile infection (CDI) rates, antibiotic use data, and whole genome sequencing to determine whether declining CDI rates were more likely driven by reduced antibiotic use or by transmission prevention efforts. The results are nicely summarized in Figure 2 from their manuscript (see below). It's extremely cool to see how the big reduction in fluoroquinolone (FQ) use from 2005-2007 was followed by the near-extinction of FQ-resistant isolates. The disappearance of these FQ-R genotypes accounted for the entirety of the significant CDI reduction seen in Oxfordshire. If infection prevention approaches were a major driver of the CDI reduction, one would've expected to see at least some reduction in the non-FQ-R genotypes. Equally interesting: as FQ use crept up, rates of FQ-R CDI didn't follow, possibly due to eradication of these genotypes from asymptomatically colonized, or due to the still-lower usage (or usage in different populations). Anyway, there's a lot of great detail in this report, so read it yourself, but the results support the centrality of stewardship to CDI prevention. LATE ADDENDUM: See this post by Marc Bonten and this Wellcome Open Research article for important caveats to the above “simple interpretation” of this study.

Anderson, et al. Lancet 2017. I'm kind of embarrassed that we haven't weighed in on this one yet, since the Benefits of Enhanced Terminal Room (BETR) Disinfection study is definitely “BETR” than most infection prevention studies. It's a cluster-randomized, multicenter, crossover study that compares standard disinfection to bleach, UV-C, and bleach + UV-C for terminal room disinfection after occupancy by patients with MRSA, VRE, multiple-drug resistant Acinetobacter, or CDI. The outcome is acquisition of colonization or infection with the index organism by the subsequent room occupant. One reason I haven't blogged about the study yet is that I really don't know what to make of it. It's a great study, but some of the results are confusing or counterintuitive, and don't make me want to rush out and buy more UV robots (full disclosure: we have a whole army of them at our hospital already, all of which were purchased prior to the results of this study). For rational takes on the entirety of the study I'll outsource to our colleagues Jon Otter and Marc Bonten at Reflections IPC. As for the C. difficile results (see below for per-protocol results from Table 3 of the manuscript), UV-C didn't reduce CDI risk beyond that of standard bleach disinfection. For the purposes of this blog post, I'm going to concur with the authors' contention that ”the environment might not play as large a role in C. difficile transmission as previously suspected” (or at least not as large a role when you've already cleaned said environment with bleach). It's all about the antibiotic stewardship, baby!

Widmer, et al. Clin Infect Dis 2017. This is the laziest, least resource-intensive of these three studies, and also my favorite. What better way to determine whether an intervention to prevent transmission is effective than to just stop doing it and see what happens? [I'm now picturing Andreas Widmer leaning back on his office chair, feet on his desk, overseeing a decade of not placing CDI patients in contact isolation.] I'm kidding, of course, in fact they did quite a lot of sampling of the contacts of these CDI patients (451 of them) to assess for transmission events. The upshot: only 2 (!) proven (and 4 probable) transmission events were documented using genome sequencing over the decade, and no outbreaks occurred. Of note, they did place those with “severe incontinence” in contact isolation (really, this is in the spirit of Standard Precautions), and all CDI patients were assigned a dedicated toilet. Oh, and they also had no active antibiotic stewardship during this time period, but report a >90% adherence to hand hygiene (paging Eli!).

To sum up: three interesting studies, and the combined results lead me to conclude that, assuming I have a limited budget with which to reduce CDI, I'd be wise to invest most of it in active antibiotic stewardship.

Daniel J. Diekema, MD, FACP, practices infectious diseases, clinical microbiology, and hospital epidemiology in Iowa City, Iowa, splitting time between seeing patients with infectious diseases, diagnosing infections in the microbiology laboratory, and trying to prevent infections in the hospital. This post originally appeared at the blog Controversies in Hospital Infection Prevention.