Negative study of the month, C. difficile edition

I like a good negative study, particularly when it’s a multicenter randomized trial about preventing our most problematic healthcare-associated infection. So let’s take a moment to appreciate this work from Amy Ray and colleagues.

These investigators randomized 16 hospitals to either standard cleaning or “enhanced cleaning”, which meant monitoring of environmental services personnel with feedback of performance (measured using fluorescent markers for cleaning and environmental cultures for disinfection). They measured the outcome of healthcare-onset, healthcare-facility associated C. difficile infection (HO-HFCA CDI). The study was powered to have >95% power to detect a 25% reduction in HO-HFCA CDI in intervention hospitals (and 70% power to detect a 15% reduction).

Bottom line: the intervention led to clear improvement in cleaning (better removal of fluorescent markers) and disinfection (reduction in % of C. difficile + environmental cultures in CDI rooms from 13% to 3%--which was the approximate rate of contamination in non-CDI rooms). Unfortunately, there was no reduction in HO-HCFA CDI during the intervention period, and no difference between control and intervention hospitals (see figure below and article for details).

Few people know more about CDI than Curtis Donskey (senior author of this study), so I encourage you to read their interpretation of these negative findings. They cover several potential explanations--the one I find most convincing is that the portion of HO-HCFA CDI attributable to organism acquisition during hospital admission may be smaller than we realize. Thus I agree that we need more studies to help us “identify effective strategies to reduce the incidence of healthcare-associated CDI.” 

I’ve already weighed in with my opinion on the most effective strategy.

Anyway, bravo to Ray and colleagues for an excellent addition to our knowledge about CDI prevention!

Hospital Floors Linked to Pathogen Transmission

Years ago, when faced with an MDR-Acinetobacter baumannii outbreak, I recommended that our hospital implement shoe covers in the outbreak unit (along with other measures) since the floors were covered with Acinetobacter. Since then, I've been almost surprised by the continued lack of attention that floors (and even contaminated shoes) have received from my infection prevention colleagues. Fortunately, it seems, some folks are finally noticing and estimating the role that contaminated floors play in pathogen transmission in hospital settings. And by "some folks", I mean Curtis Donskey's group at the Cleveland VA.

In a study, just published in ICHE, Sreelatha Koganti and colleagues used non-pathogenic bacteriophage MS2 to measure the speed of spread from isolation room floors to patients' hands and high-touch surfaces inside (and outside!) their rooms.

First, I would like to quote from their background:

"Notably, hospital floors are often heavily contaminated but are not considered an important source for pathogen dissemination because they are rarely touched. However, floors are frequently contacted by objects that are subsequently touched by hands (eg, shoes, socks, slippers). In addition, it is not uncommon for high-touch objects such as call buttons and blood pressure cuffs to be in contact with the floor (authors’ unpublished observations). Therefore, we hypothesized that floors might be an underappreciated reservoir for pathogen transmission."

And now their results:

"MS2 was detected on multiple surfaces of all patient rooms by 1 day after inoculation... Contamination was common on high-touch surfaces in adjacent rooms, in the nursing station, and on portable equipment. Portable equipment included wheelchairs, medication carts, vital signs equipment, and pulse oximeters."

What was most surprising was that MS2 was detected on 40% of patients's hands on Day 1, 63% on Day 2 and 43% on Day 3 after the floors were inoculated. Wow.

Now, after years watching our non-responses to epidemiological data such as these, I can already foresee the responses. Most will continue to do nothing waiting for some mythical/magical cluster-randomized trial, which can't be done for economic reasons (try powering such a study). Others will ignore these results completely. And a few brave souls will soldier on with more excellent epidemiological investigations, like this study from Cleveland, hoping that people will eventually notice. Oh, and some will install copper floors.

Maybe we could start with cleaning patient-room floors daily?

image source: DailyMail.com

Guest Post: AHRQ Report Calls for Environmental Cleaning Research

This guest post was written by Alexandra McGhie, Megan Campbell and Nick Graves to highlight a new AHRQ Report as it relates to an NHMRC (Australia) Partnership Grant led by Queensland University of Technology (QUT) & The Wesley-St. Andrew’s Research Institute (WSARI) called REACH.

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New report calls for further research examining the impact of environmental cleaning interventions on Healthcare Associated Infection (HAI) rates

A new report by the US Agency for Healthcare Research and Quality (AHRQ) calls for further studies on emerging strategies for environmental cleaning and their impact on healthcare associated infection rates.

The report, Environmental Cleaning for the Prevention of Healthcare-Associated Infections (Technical Brief Number 22) details a systematic review of 80 studies that aimed to  determine the evidence base and comparative effectiveness of environmental cleaning methods and monitoring strategies of frequent touch surfaces in hospital rooms. The report concluded there was a lack of studies directly comparing cleaning methods and monitoring strategies, and calls upon the research community to undertake further research that:

·       Examines and compares emerging strategies (including ATP and UV light technologies).

·       Includes patient colonisation and infection rates as outcome measures.

·       Identifies surfaces in hospital rooms posing the greatest risk of pathogen transmission.

·       Examines factors that affect the real-world implementation of cleaning interventions (organizational culture, training, feedback).

An obvious omission to the report is that the value for money of any change to practice is not considered. Current health spending growth will not continue as it has. And infection prevention communities must think about the returns per dollar spent on new programmes.

Both effectiveness and cost-effectiveness evidence for a new ‘bundle’ approach to hospital cleaning will be generated by the REACH project. The effect on the transmission of healthcare associated infections (HAIs) in eleven Australian hospitals will be estimated and the value for money assessed.

The randomised controlled trial funded by the an NHMRC Partnership grant (GNT1076006) is led by QUT and The Wesley-St. Andrew’s Research Institute (WSARI) in conjunction with industry, policy and professional partners.

For more information about the REACH Project, please visit:  http://reach.cre-rhai.org.au/

The post originally appeared on the AusHSI Blog.

Say what?! Colonized patients (but not infected patients) contaminate the hospital environment

There is a continuous debate in infection control about whether to actively screen patients for MDRO colonization and subsequent isolation. Alternatives to active screening include passive surveillance, where only patients found to be infected through clinical cultures are isolated. Frequently, passive surveillance is justified by saying that infected patients will have a higher bio-burden compared to colonized patients, so they would be more likely to contaminate healthcare workers hands and the environment. However, is this in fact true? Are infected patients more likely to contaminate their rooms than colonized patients?

In part to answer this question, Lauren Knelson and colleagues from Duke and UNC just published a study in the July ICHE that measured the contamination of rooms after patients colonized or infected with MRSA or VRE were discharged. 48 rooms (33 from colonized patients, 15 from infected patients) were sampled using Rodac plates after patient discharge but before terminal room cleaning. Numerous sites were sampled including: sinks, toilet seats, bedside tables, bed rails, chairs, floors, TV remotes, carts, and laundry bins. This is a very small study, but even with the limited sample size they found that median CFU were higher in colonized vs infected patients' rooms (25 CFU vs 0 CFU, p=0.033). As you can see in the figure, the distribution of room contamination was greatly skewed towards higher levels of contamination at discharge from colonized patient rooms.

Some caveats: (1) More surfaces were sampled from colonized patient rooms than infected patient rooms (6.52 ± 2.47 surfaces vs 4.07 ± 2.12 surfaces; P = .02), so it's possible that surface selection could have biased these findings; and (2) Colonized patients stayed twice as long prior to discharge as infected patients (median 16 vs 7 days, p=0.28). Even though p > 0.05, this could be important since occupied rooms aren't "terminally cleaned" and "time in room" must increase contamination.

If these findings are validated, they have important implications. First, isolating infected patients (passive surveillance) would be expected to have less utility than expected. Second, the significant contamination of colonized patient rooms prior to terminal cleaning should be a reminder that we need to identify and implement environmental cleaning technologies that work continuously during the patient stay and not just focus on terminal cleaning. Finally, since infected patients would have received effective therapeutic antibiotics, these findings support the idea that effective antibiotics are important adjuvants for infection control. If true, this suggests that as the MDRO crisis expands in the absence of novel antibiotic discovery, infection control will become far more difficult (see 2011-2012 NIH KPC outbreak).

The copper kerfuffle, continued:

Several months ago we invited a guest post from Stephan Harbarth and Matthias Maiwald, a post that questioned the biological plausibility of a recently published clinical trial of copper surfaces that claimed a more than 50% reduction in the rate of healthcare-associated infection (HAI) and/or MRSA-VRE colonization. Now Harbarth, Maiwald and Stephanie Dancer have published a more extended critique of the study in a letter-to-the-editor in the September issue of Infection Control and Hospital Epidemiology. I encourage you to read the letter, and the reply from the authors, and make up your own mind about the validity of the findings and the transparency with which the authors reported their outcomes.

My two cents: the authors’ have been caught out in a case of selective reporting (or at least egregious obfuscation) of their outcomes, and it would probably have been better for them not to issue a reply (mostly because the reply is not persuasive). The reply claims that “any HAI” wasn’t reported because it would have also included some patients with colonization, and the development of infection versus colonization may be biologically different. But it is still OK to report the outcome “HAI and/or colonization”? They also make the case that Harbarth, et al cannot question the biological plausibility of their findings because they themselves have also argued that the environment is a source of HAI pathogens. This of course misses the point entirely. Harbarth, et al aren’t arguing that the environment has no role, they are arguing that it is implausible, given what we know about the pathogenesis of HAIs, that the environment has the major role suggested by the findings of this study.

A well-designed, persuasive, multicenter, randomized controlled trial that demonstrated a greater than 50% reduction in HAI by changing high-touch surface composition should have been published in a very high impact journal (e.g. JAMA, NEJM, Lancet), and the findings should have been front-page news in major media outlets. Alas, that didn’t happen with this study, for some of the reasons outlined in the letter by Harbarth, et al.