Is it time to ditch CHG bathing in ICUs and get back to basic infection control?

We are at an interesting inflection point in infection control. On the one hand MRSA is in decline and VRE has flat or declining incidence in many national samples. Yet on the other, we have largely pulled back from what is considered traditional infection control practice. It is important for us to understand what may be driving the declines in MRSA (and to a lesser extent VRE) and on what shaky foundation these declines are actually resting.

The recent MRSA decline is due to multiple factors including the underlying epidemiology of the pathogen, host immunity and the emergence of effective antibiotics targeting MRSA that are not named vancomycin (e.g. linezolid, daptomycin, ceftaroline). These factors are intertwined. For example, recent CA-MRSA strains have susceptibility to many existing antibiotics (e.g. clindamycin, tmp-sulfa), which highlights the complexity of the underlying reasons for MRSA's decline. I should also mention the antibiotics CHG and mupirocin here too, but I'll get back to them in a bit.

During the past decade, we've also seen a decline in the importance of basic infection control. Many of you will disagree with this statement but let me explain. The cornerstone of infection control has always been hand hygiene compliance and yet very little "honest" attention is paid to it. There is now so much pressure to report hand hygiene compliance rates greater than 90% that we have hit the target without actually improving compliance. Over and over in studies at hospitals across the US where we've looked, hospitals are reporting compliance rates over 90% and it's actually 40-60%, when we look closely with independent observers. Why does this matter? Because when we believe it's 90%, we ignore it.

On top of our hand hygiene conundrum, contact precautions are no longer favored for MRSA prevention. A bit of history - the second ever post on this Blog back in 2009 was titled: "Why I hate Contact Precautions, vol. 1." So there's not much love here for ye olde CP. Which brings me to the point of this post (finally) - when we no longer have hand hygiene compliance, gowns and gloves and when the foundation of infection control is based on antibiotics like linezolid, CHG and mupirocin, what will we do when the foundation begins to crumble?  Will we even notice the crumbling or will we stick our heads in the sand and ignore it?

Many of the gains in infection control over the past decade have rested on the foundation of CHG bathing. Ignoring for now that CHG might select for Gram-negative pathogens that have fewer effective therapies, CHG use might also select for CHG resistance through efflux pumps coded by qacA/B, which has been associated with MRSA decolonization failures. Yet the long-term (and after a decade, we are getting longish) effects of daily CHG bathing are not well described.

Into this void, David Warren and colleagues just reported in ICHE 8-year trends in the epidemiology of MRSA strains after initiating daily CHG bathing in their SICU. A random sample of 504 MRSA isolates were selected for analysis (63/year). Among all isolates from 2005 (when CHG bathing was implemented) to 2012, 7.1% were qacA/B(+). Somewhat disconcerting was the rise of qacA/B from 6.2% (2005) to 16.9% in both 2009 and 2010. Also concerning was the finding that 25% of qacA/B(+) MRSA isolates were mupirocin resistant. Results stratified by timing of nasal swab collection are in the Figure above. In explaining this increase the authors noted: "qacA/B(+) isolates from 2009 and 2010 were more likely to have ≥1 hospital admissions in the prior year, suggesting a possibility of an expansion of qacA/B(+) MRSA at BJH during this time period, which resulted in qacA/B(+) patients in those years being exposed in prior admissions."

So where do these findings leave us? Yes, more studies, larger studies, bigger and better studies - $6 million dollar man studies. But pending those dream-like studies, can we state at what level of CHG resistance we should ditch universal CHG bathing?  Are we compromising the effectiveness of CHG in preoperative settings like those supported by STOP-SSI? And when can we get back to basic infection control? To my knowledge hand hygiene and gowns/gloves don't drive resistance like CHG. Well, except resistance from my esteemed co-bloggers and colleagues. ¯\_(ツ)_/¯


  1. although I appreciate much of what Dr. Perencevich so eloquently stated, I reviewed the paper pondering a few other issues - just how many hospital or rehab days or even lives were saved by preventing an invasive S. aureus infection among patients in that ICU.
    Also, the presence of these genes have not become clinically relevant I believe, but I am probably not up to speed on this.
    I know CDC has tapped down its inflow of bloodstream infection isolates for study, but historically these genes have been rare to non-existent in clinical invasive isolates. Hopefully tracking the emergence or persistence of these genes can be done if expansion occurs.
    Regardless, I think the evidence of decreasing MRSA infections in healthcare precedes widespread use of CHG...but perhaps CHG will be a useful tool to have greater impact; we just need to find the right mix of high risk patients, safe use, and reasonable detection of clinically relevant resistance. Although the drops seen the Emerging Infections Program data
    may reflect infection control success (note hospital-onset disease has dropped greatly; but not community-based infections), or pre-emptive treatment among inpatients, I do think these data suggest hospital activity has affected hospital-onset disease....however as outlined by warren, we are continually confounded (maybe befuddled is a better word) by patients presenting to the hospitals with the potentially bad pathogen on their skin, catheters, and various biofilm spots. CHG offers patients a tool to prevent advancement from carriage to infection that has implications beyond the ICU and even hospital setting. I think its here for the long haul; lets figure out how to best integrate it responsibly.

    1. Thanks for your comments. Definitely think CHG is here to stay, but not sure how long it will be effective. Do we need to bathe everyone or select high-risk patients as you suggest - "responsibly" is a good word. For example, I could design a study where everyone gets carbapenem+vanco on admission and show reduced HAI, lives saved etc. We select who we give systemic antibiotics to (if a bit poorly), we should probably due that with topical antibiotics like CHG.

    2. Scott - just a question for you - how would we define/detect whether "the presence of these genes have..become clinically relevant" I thought the presence was associated with decolonization failure?

  2. I disagree with your premise, Eli, that we have abandoned basic infection control. Our new infection prevention campaign that is about to rolled out at the University of Iowa Hospitals and Clinics focuses healthcare workers on 3 things: hand hygiene, stethoscope wipe down, and bare below the elbows. It doesn't get more basic than that.

    I should also point out that our recent implementation of chlorhexidine bathing is very tightly temporally associated with a 50% reduction in our CLABSI rate. We will continue to push chlorhexidine bathing.

    1. Mike, this was not a comment on UIHC or any hospital in particular. Using your UI or VCU example as representative is not science and most hospitals don't have the program we have here at Iowa but they are using CHG with HH compliance at 10%. I will also strongly defend my comment that everywhere that believes their hand hygiene compliance is near 90% is in denial. I'm not aware that anyone has developed new interventions designed to improve hand hygiene compliance since the advent of alcohol hand rub in the late 1990's and early 2000's. So society/the world isn't doing much except developing HH surveillance technology.

      As far as CLABSI, my take is that CHG bathing is a cover for poor compliance with the CLABSI bundle (which includes CHG) and also a cover for very poor hand hygiene compliance in the WHO 5 Moments (moment 2 specifically).

      I realize I have lost the battle since everyone loves bathing their patients in antibiotics (CHG) and I expected you to disagree. But I think you are completely wrong on this in the long run. CHG will shift to GNR and select for resistant SA and MRSA. Just a fact.

      Probably best not to look - going to be too painful

    2. I agree you with you that my experience isn't science. A long time ago, Dick Wenzel wrote, "Infection control is an art, a science and a business." Having been a practicing epidemiologist for 2 decades, I can tell you that I have never waited on science to guide my practice. I'm not a purist and I prefer to march ahead of science. So in reality, much of my practice is an art. The lag between science and practice can be far too long, and patients and senior hospital leaders aren't going to wait. They want results now, and I agree with them. You weigh the potential risks and benefits, and in the case of chlorhexidine, I still believe the benefit greatly outweighs the risk.

    3. Indeed - much is art and where and with whom we've trained. Buried in the comments here I can share that when I was a hospital epidemiologist, we had an MDR-AB outbreak possibly and perhaps likely driven by universal CHG bathing. This outbreak was only controlled by universal gown and gloves. And you might agree that the dire future of infection control rests in how well we prepare for MDR-GNR. So, as folks slam contact precautions (not using good scientific data but more belief) and dive into CHG, I would just ask that alternative experiences be considered. Others might not have 20 years in the field, but I just crossed 15.

  3. Glad to read the rich discussion. Hard to know the future, but it does seem relevant that CHG is the only intervention that has convincing RCT data for use (unlike hand hygiene or CP). Not that there aren't limitations say with an outcome of "bacteremia" that appeared to be contaminants more than pathogens. Still, would tend to stick with proven benefit of CHG bathing in high risk patients without being overly alarmist about hints of yet unproven limitations to CHG.


    1. Of course, we know that it is next to impossible to design and power studies to show benefits of interventions that prevent transmission. The core of this is that very few transmission events result in infection and detecting transmission events is difficult (admission/discharge swabs - but where do we swab and how sensitive are swabs at detecting transmission and timing of swabs and what about incident events after discharge) I could go on.

      It is much much easier to undertake trials of antibiotics that work for individual patients and prevent infections- CHG etc. Far lower bar to hop over.

      What I'm saying is, our field needs to think longer and harder about how we move forward and CHG is part of the answer but right now it's the only answer really. And I mostly worry about MDR-GNR and CHG is probably not a great answer there.

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