Attacking the fecal veneer*

What an excellent start of 2017. A great study from the USA today in Lancet: In a pragmatic cluster-randomized crossover study they tested 4 patient room cleaning strategies on the effectiveness to reduce acquisition with relevant bacteria for the incoming patients. The conclusion states that “enhanced terminal room disinfection decreases the risk of pathogen acquisition.” Yet, this paper is so “data-dense” that you must read the methods (and supplements) to get the picture. In one shot: Not for C. diff, may be for MRSA and yes for VRE.

It is a no-brainer that bacteria-contaminated rooms can contribute to pathogen acquisition. Yet, that contribution has seldom been accurately quantified, and, thus, we had no idea what to expect from innovative and/or expensive new techniques to clean rooms, after a patient with pathogen X left a room (this is called terminal room disinfection). In this study they tested 4 strategies, each during 7 months, in random order in 9 hospitals in single-patient rooms from which a patient on contact precautions had been discharged or transferred. The outcome was acquisition of C. diff, MRSA, VRE or multiresistant Acinetobacter for the incoming patient.

The 4 strategies:

  1. Disinfection with quaternary ammonium-containing disinfectant (reference);
  2. Reference + a UV-C device (UV-group);
  3. Disinfection with a hypochlorite-containing disinfectant (bleach group);
  4. UV+bleach

Importantly, in rooms with C. diff only the bleach containing strategies were used!

In just over 2 years they had 31,226 (!!!!!) rooms that met the inclusion criteria, yielding 21,395 patients with 97,833 exposure days eligible for the intention-to-treat analysis (all >24 h in room and without community-onset carriage/infection). In the primary analysis the relative risk of any pathogen acquisition was, compared to reference, 0.70 (0.5-0.98) in the UV-group, 0.85 (0.69-1.04) in the bleach group and 0.91 (0.76-1.09) in the UV-bleach group. I crack my brain on what they did with C. diff as these patients (>5,100) were not in the reference group……

So, let’s look at the pathogen specific results:

Adding UV-light to bleaching did not (at all) reduce the risk of C. diff acquisition. Adding UV-light to the reference tended to reduce MRSA-acquisition (RR 0.78 (0.58-1.05)), but UV-light + bleach appeard less effective (RR 0.97 (0.78-1.22), and bleach alone did nothing (RR=1.00).

The largest effects were seen for VRE with RRs of 0.41 (0.15-1.13) for UV-light, 0.43 (0.19-1.00)  for bleach and 0.36 (0.18-0.70) for bleach+UV. There was only 1 acquisition with a multiresistant Acinetobacter, so no data for that.

So, what to do now…….? This great study – for the first time – provides measures of relative effectiveness of disinfection procedures. The strongest signal comes for preventing acquisition with VRE, which I like as it confirms results from a study in which I participated 10 years ago. The results for C. diff and MRSA are much less (or not) convincing.  Please, do read the discussion for important aspects (for instance in how UV-lights were used) essential for the correct interpretation and extrapolation of these results.


*term patented by Robert A. Weinstein for VRE (only)


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