REDUCE MRSA: Readers weigh in!

In my short post about this study last week, I promised that I’d follow up with the most likely criticisms we’ll be reading in future letters-to-the-editor. My post was going to focus on concerns about emerging resistance to topical agents, the lack of impact on MRSA bacteremia, and the outsized influence of skin commensals on the outcomes (see my post on the chlorhexidine bathing studies).

Fortunately, our readers have done this work for me. Below I’ve excerpted a comment we received today:

"We applaud investigators for their hard work in completing a high quality study. However, it has limitations and recommendations are overreaching.

--The intervention

Mupiricin/Chlorhexidine for all patients is very aggressive. Would chlorhexidine alone work in a similar fashion? (resistance is a real concern, especially for mupiricin, and if these agents become inactive they can't be used on high risk patients) We don't really know, but there will be calls to vastly increase antimicrobial exposure to mupiricin based on a study with a mixed intervention that prevented relatively few MRSA clinical cultures even over 74 ICUs I.E. A LOT OF PATIENTS WILL RECEIVE MUPIRICIN FOR A VERY SMALL ABSOLUTE DECREASE IN POSITIVE MRSA CLINICAL CULTURES!

--Outcomes

Bacteremia rates were elevated in the intervention arm during baseline period (6.1 vs. 4.8 or 4.2). Overall bacteremia rate was nearly 50% higher in ICUs that were randomized to the intervention! The intervention itself brought bacteremia rates down to what they already were in other ICUs.

The effect on bacteremia was mostly skin commensals such as coagulase negative Staphylococcus. As in Climo et al, this is probably the least important organism and may relate to decreasing contamination rates. We think this point is also important in the Climo paper, chlorhexidine bathing only had an effect on VRE acquisition and not MRSA acquisition and only had an effect on coagulase negative Staphylococci and candida bacteremia.

MRSA Clinical Cultures are a mixed group of colonization/infections that vary depending on sites. Is MRSA in the sputum the same as MRSA in a deep surgical wound? Or urine culture? or superficial wound culture? Did the frequency of culturing change during the intervention. Given data was obtained from a datapull, all of these questions could be answered which would help interpretation of this trial.

Although the trial is being hailed as a nail in the coffin of active surveillance culturing for MRSA, there are potential harms with over interpretation of the trial. If we begin using mupiricin and chlorhexidine on all ICU patients nationwide, as our European colleagues have suggested will occur, we may eventually have as many problems from the study as early studies of ASC. We also think that one cluster randomized trial should not change practice in such a sweeping manner.

From a more cautious perspective, this trial and Climo et al support that chlorhexidine bathing likely has a benefit on infections in the ICU. It isn't a huge effect and it is predominantly on markers that aren't as important (MRSA clinical cultures and coagulase negative Staphylocci AND CANDIDA (and VRE for Climo)). However, it should be considered by hospital ICUs with problems in these infections.

We should be worried that ASC may be finished only to be replaced by an equally problematic mandate (that more than swabbing every patient is actually treating every patient)."

We will also soon feature a guest blogger from a healthcare system with a long history of using active surveillance for MRSA control.  He also has quite a lot to say about REDUCE MRSA. We welcome all of our readers to weigh in, please feel free to do so in our comments section! The name of this blog begins with the word "controversies", after all....