Antimicrobial resistance visualized

Click here to view an amazing video that dramatically visualizes the development of antimicrobial resistance.

Hat tip: Brian Hoff, PharmD

Disaggregating the Benefits of Ventilator Bundle Components

There is a very nice study by Michael Klompas and colleagues in September's JAMA Internal Medicine. The team sought to disentangle the benefits or harms of the individual components of current ventilator bundles including: head-of-bed elevation, sedative infusion interruptions, spontaneous breathing trials, thromboprophylaxis, stress ulcer prophylaxis, and oral care with chlorhexidine.

Prior studies had found potential harm associated with stress ulcer prophylaxis (pneumonia) and oral chlorhexidine (higher mortality). This same group published a meta-analysis that called into question the benefits of routine oral care with chlorhexidine (CHG) in ventilated patients. For this retrospective cohort, they examined the associations between exposure to individual ventilator bundle components on a day-by-day basis and ventilator-associated events (VAEs), duration of mechanical ventilation, ventilator mortality, hospital length of stay, and hospital mortality.

The cohort included 5539 consecutive patients who were exposed to mechanical ventilation for at least 3 days. They measured the association between individual process measures and VAEs using Cox proportional hazards regression models with fixed and time-varying covariates and censored patients on extubation or death, whichever came first. Interestingly, they calculated hazard ratios for each bundle component "as the contrast between 4 days of continually performing the process measure vs 4 days of not doing so", since they wanted to allow for the possibility that process measures might have an immediate or delayed effect on each outcome.

I have included the patient-outcomes table below. The most interesting finding, among many tested associations, was that oral care with chlorhexidine was associated with an increased risk for ventilator mortality (HR, 1.63; 95% CI, 1.15-2.31; P = .006). In another table, they reported that stress ulcer prophylaxis was associated with an increased risk for possible ventilator-associated pneumonia (HR, 7.69; 95% CI, 1.44-41.10; P = .02).

This was a very thoughtfully completed and written study - I encourage you to read it (and the accompanying invited editorial) beyond my quick overview. The authors concluded: "we should revisit the classic ventilator bundle. Possible revisions include... a reappraisal of whether oral care protocols should be revised to exclude chlorhexidine therapy, and the reservation of stress ulcer prophylaxis for patients at marked and immediate risk for upper gastrointestinal tract bleeding rather than prescribing them for all patients undergoing ventilation."  It will be interesting to see how slowly these recommended changes occur...

"CAUTI"

There's an excellent commentary on urinary tract infections in the American Journal of Medicine by Tom Finucane, one of my professors from medical school, who is a superb general internist and geriatrician. He argues that UTIs are overdiagnosed and overtreated, and notes that uncomplicated cystitis is usually self-limited, as evidenced by the billions of persons who have recovered from UTIs without antibiotics. And he cites recent studies that challenge the long-held dogma that urine is normally sterile.

What is needed, Dr. Finucane tell us, is a paradigm shift on how we think about UTI. To that end, he suggests "that authors use “UTI” only within quotation marks and that clinicians use the bimanual “air quotes” gesture in discussions. This small, repetitive annotation is intended to disrupt the term’s complacent usage and encourage rethinking of how one manages bacteriuria."

On reading his commentary, I couldn't help but think of posts on the blog over the past few months that question the importance of and even the existence of CAUTI "CAUTI." 

Image: GIPHY.

Goodbye Triclosan (and Triclocarban)

Back when I was an ID fellow, I completed a national survey (along with Anthony Harris) of the availability of tricolsan and triclocarban containing antibacterial soaps. At the time, the industry wouldn't release the use or sales data we needed to estimate a population risk from these chemicals. We found that 76% of liquid soaps and 29% of bar soaps sold to consumers contained these agents. Fifteen years ago we concluded: "with limited documented benefits and experimental laboratory evidence suggesting possible adverse effects on the emergence of antimicrobial resistance, consumer antibacterial use of this magnitude should be questioned."

Well, patience is a virtue. Today, the FDA issued a rule banning triclosan, triclocarban and 17 other agents in hand soaps and body washes. The ban does not apply to antibacterial soaps used in healthcare settings. In a press release, the FDA stated:

"there isn’t enough science to show that over-the-counter (OTC) antibacterial soaps are better at preventing illness than washing with plain soap and water. To date, the benefits of using antibacterial hand soap haven’t been proven. In addition, the wide use of these products over a long time has raised the question of potential negative effects on your health."

It's nice to see positive change happen in your lifetime. It's also nice not to have to read a soap's ingredients before washing our hands.

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