Fear the "freely evolving turbulent puff cloud"!

It’s well worth your time to check out a great video recently published in NEJM by Dr. Lydia Bourouiba (from the MIT Fluid Dynamics of Disease Transmission Laboratory). Simply entitled “A Sneeze”, the images and videos graphically demonstrate the biological plausibility of the findings Eli describes in his recent post on presenteeism.

In her description, Dr. Bourouiba writes:

"[The video]…shows a turbulent cloud that consists of hot and moist exhaled air, mucosalivary filaments and drops, and residues from droplet evaporation (nuclei). The ejection lasts up to 150 msec and then transitions into a freely evolving turbulent puff cloud. The largest droplets rapidly settle within 1 to 2 m away from the person. The smaller and evaporating droplets are trapped in the turbulent puff cloud, remain suspended, and, over the course of seconds to a few minutes, can travel the dimensions of a room and land up to 6 to 8 m away.”

Thanks to John Boyce for pointing this out on the SHEA Open Forum (join SHEA to sign up!).

Paid Sick Leave: Avoiding Contagious Presenteeism and Preventing Influenza

The US of A is the ONLY industrialized country without nationwide access to paid sick leave. Reread that sentence several times to let it sink in, it's OK, I'll wait for you. Opponents of paid sick leave say that mandatory sick leave increases the cost of labor and hurts job creation. In addition, they suggest  that paid leaving increases shirking behavior and "noncontagious absenteeism". However, there are potential economic benefits for paid leave, particularly in regards to encouraging workers to not work when they've acquired an infectious disease - "contagious presenteeism."

Before wider adoption of mandatory paid sick leave in the US, it is likely that the health and economic value of such mandates will need to be estimated. To that end, economists Stefan Pichler and Nicolas Ziebarth have just published an unreviewed working paper in the National Bureau of Economic Research, that sought to estimate the impact of paid sick leave on labor supply and avoiding presenteeism as manifest through reduced influenza cases. They were able to take advantage of the staggered implementation of several city (San Francisco, Washington DC, Seattle, Philly, Portland and New York City) and state (CT, CA, MA, OR) sick leave mandates in order to determine the reduction in population-level influenza-like illness (ILI) cases using Google Flu data (2003-2015). Other cities, and states not covered by the mandates served as controls. 

When they examined the impact of the mandates using city-level data and difference-in-differences models, they found that gaining access to paid sick leave resulted in a 5.5% reduction in ILI per 100,000 doctors visits. When analyzed using state-level data, they found a 2.5% reduction in ILI after adoption of mandatory sick pay. Importantly, the authors state that "infections rates may further decrease in the medium to long-run when employees have accrued larger amounts of paid sick days." The paper then takes a deep dive into the underlying behavioral mechanisms of these programs (contagious presenteeism and noncontagious absenteeism) and the positive and negative aspects of mandatory sick leave using US and German data, which makes for interesting reading if you have time. 

The findings of this paper suggest an important population-level benefit for mandatory sick leave policies, which suggests the US should consider passing a bill to make such a policy nationwide. In fact, President Obama said this during his 2015 State of the Union Address: “Send me a bill that gives every worker in America the opportunity to earn seven days of paid sick leave. It’s the right thing to do. It’s the right thing to do.” I'm thinking more mandatory sick leave and less influenza would make America a wee bit greater.

Image Source: nyc.gov

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

Survey on Environmental Cleaning and Disinfection

Our colleagues at the Infection Prevention & Control working group in the International Society of Chemotherapy for Infection and Cancer (ISC) have developed an anonymous survey on environmental cleaning and disinfection and they'd really like your input. Thanks to Ermira Tartari for forwarding the survey. I've posted the group's letter and link to their survey below. Thank you.

Dear Colleague,

On behalf of the International Society of Chemotherapy for Infection and Cancer (ISC), the Infection Prevention Control working group, we would be grateful if you could complete this anonymous survey.

Our aim is to provide a perspective on cleaning and disinfecting practices in hospitals internationally. Your input would be very valuable. The questionnaire should require 15 minutes to complete. Please find the link to the survey below. Feel free to share the survey and encourage as many of your colleagues from various health care facilities.

If you wish to participate and be acknowledged, kindly forward us your name and institution by sending a separate email to: secretariat (at) ischemo.org.

If you wish to participate, you can find the questionnaire here:

https://www.surveymonkey.com/r/Environmental_Cleaning_Survey 

In anticipation,

Nikki Kenters and Tom Gottlieb

The skullcap feud

There's a feud brewing between two professional societies on appropriate attire in the operating room. Earlier this year, AORN (the Association of periOperative Registered Nurses) issued updated guidelines on OR attire. The guideline forbids the wearing of skullcaps because the head covering should cover the head, hair, ears, facial hair, and nape of neck when personnel enter the semi-restricted and restricted areas of the OR. This didn't sit well with some surgeons, and the American College of Surgeons (ACS) issued their own statement on OR attire earlier this month. With regards to the skullcap, they state, "the skullcap is symbolic of the surgical profession. The skullcap can be worn when close to the totality of hair is covered by it and only a limited amount of hair on the nape of the neck or a modest sideburn remains uncovered. Like OR scrubs, cloth skull caps should be cleaned and changed daily. Paper skull caps should be disposed of daily and following every dirty or contaminated case."

From AORN's perspective, the issue with skullcaps is the exposed ears and exposed hair at the base of the head, from which pathogens may contaminate the surgical field as hair and skin squames are shed. The counterargument, of course, is that there is no evidence to suggest that skullcaps have been associated with surgical site infections. And now we find ourselves in essentially the same quagmire as with white coats.

This week, AORN shot back, and they punched the good old boys right in the gonads. Says AORN, "head coverings based on symbolism and a personal attachment to historical norms have no place in the patient benefits analysis expected of guidelines developers." AORN rightly took the moral high ground and called out the ACS for using a professionalism argument to justify their stance. As I have argued before with regards to the white coat, professionalism exists to protect the profession, not the patient. So while the surgeons' argument with regards to lack of evidence has validity, the professionalism argument does not. And my thinking about the skullcap is the same as for the white coat: the biologic plausibility for causing infection should lead to a suggestion to avoid the skullcap but not a mandate. While AORN may argue that their recommendations are guidelines, the reality is that the Joint Commission enforces them as mandates.

I'm not a surgeon, but if I were, I'd give up my skullcap, just in case bacteria were falling off my earlobes. And I think these issues are much easier to resolve if we simply follow the dictum, the patient comes first in everything that we do.

While I'm on my moral high horse, and since I'm an equal opportunity critic, I'd be remiss if I didn't point out an issue with the AORN. You may have noticed that there is no link to the AORN attire guideline in this post, and that's because AORN sells their guidelines for $225. It seems to me that when any professional society has something so important to say that it is written into a guideline, they have a moral imperative to make the guideline accessible free of charge to everyone, particularly when the guideline impacts patient safety. This is but another example of the ugly side of professionalism, a decrepit concept that continues to haunt us.

We need to implement shoe decontamination interventions!

You pass through places and places pass through you 

But you carry them with you on the soles of your travelers shoes

"The Littlest Birds" - The Be Good Tanyas

I know we really shouldn't be looking for other interventions to reduce pathogen transmission in hospitals since we're too busy eliminating contact precautions at the moment. But I can't resist highlighting this recent systematic review on contamination of shoe soles from Tasnuva Rashid and colleagues published in Journal of Applied Microbiology. 

The authors reviewed the published literature from 1946 through 2015 to identify studies evaluating (1) shoes as vectors for infectious pathogens and (2) evidence on possible decontamination strategies.  Their extensive review identified 13 studies (10 cross-sectional and 3 longitudinal) for inclusion. Three studies were completed in hospitals. One study found MRSA and VRE on 56% of physician shoes before rounds and 65% after rounds. Two additional studies found significant contamination of operating theater shoes with pathogens including staphylococcus, streptococcus and bacillus species. It doesn't get any better when looking at shoes worn in the community with significant contamination by C. difficile (40%), Listeria spp., Salmonella spp., and E. coli. I won't even mention the contamination found on the shoes of folks that work with animals. 

Possible interventions evaluated include placing chemical filled mats in OR and ward entry points and shoe covers. While the reviewed studies suggest possible benefits for these interventions, more studies are needed. Of course, you know where I'm heading based on my intro paragraph - we need to implement shoe covers and chemical mats immediately in all hospitals. The data is clearly just as compelling as eliminating contact precautions based on single center studies. Oh, and we can fund these new shoe-targeted interventions using the savings generated through the elimination of contact precautions. Awesome!