Kill this spore!

This month’s issue of Infection Control and Hospital Epidemiology has an interesting article from the University of Michigan group, demonstrating that having a prior room occupant with C. difficile associated disease (CDAD) is a risk factor for CDAD. Spores are hard to kill, and survive for months in the hospital environment. Meanwhile, environmental cleaning practices are highly variable….but clearly not good enough in most hospitals to eradicate C. difficile spores from the environment during terminal room cleaning. I have nothing to add to the excellent commentary on the article by David Weber and Bill Rutala. The future of environmental cleaning likely resides in touchless technologies like hydrogen peroxide vapor/mist and UV light.

Image: Transmission EM of C. difficile spore, from the Journal of Bacteriology.

Pathogen-specific preventability?

As Mike pointed out yesterday, one of the interesting findings in the CDC CLABSI report is the difference in percent reduction by pathogen. The most dramatic reduction (73%) was found among Staphylococcus aureus, with more modest reductions among gram negative bacilli (37%), Enterococcus spp. (55%), and Candida (46%).

These findings, discussed in some detail in the MMWR report itself, are consistent with a point I made in a prior post on the preventability of CLABSIs. The CLABSI prevention bundle elements prevent infections due to organisms that gain access to the bloodstream from the catheter-skin interface. No amount of skin preparation, site care, sterile barriers and hand hygiene can prevent organisms from translocating across the gut wall of a seriously ill patient—and so far, no one has developed catheter material that can completely prevent such organisms from adhering once they do gain access to the bloodstream. Furthermore, many of the organisms that arise from gut or other peripheral sites will be misclassified as CLABSIs even if they never adhere to the catheter.

We should expect that interventions which focus on reducing bacterial burden at the catheter insertion site will have their greatest impact on skin bugs, and their least impact on common gut flora. As for getting to zero, it won’t happen until we have ways of addressing infection sources other than the catheter insertion site (and by “addressing”, I mean both improved prevention approaches and improved definitions).

Some good news for a change

Yesterday, CDC released a report on central line associated bloodstream infections (CLABSI), which showed that these infections decreased in US ICUs from 3.64 to 1.65 infections/1,000 catheter days from 2001 to 2009. This represents a 58% reduction. Of note, CLABSIs due to Staph. aureus decreased by 73%, while those due to gram-negative organisms fell by 37%. CDC estimates that up to 27,000 lives were saved due to the infections averted.

Finally we have some higher quality data that shows that HAIs in the US are indeed being reduced. This is consistent with what each of us are seeing at our own hospitals. Importantly, this did not happen spontaneously. The reduction seen is due to countless hours of hard work by hospital epidemiologists, infection preventionists, and frontline providers. So we should all take a minute or two to savor this milestone. Obviously there is still more to do, but progress is being made.

Low hanging fruit: making antibiotic treatment of skin infections less awful

I recently posted about withholding antibiotics after drainage of uncomplicated purulent skin infections. The group at Denver Health now points to another opportunity for antimicrobial stewardship when treating skin or soft tissue infections (SSTI). Believe it or not, patients admitted with SSTI do not all require treatment with vancopime (or its close relative vancopiptaz (piptamycin?)). These investigators implemented a clinical practice guideline to standardize and simplify the management of patients hospitalized with cellulitis and/or skin abscess. The guideline encouraged more judicious use of testing and imaging, avoidance of broad spectrum gram negative and anaerobic coverage, and shorter courses of therapy with earlier IV to oral transition. You can read the details here, but the guideline resulted in improvement in all areas, significant reductions in use of broad spectrum antibiotics, and no difference in clinical failure rates. The study was single center and quasi-experimental, but clearly points out an area ripe for drastic improvement in most hospitals.

The accompanying editorial by Brad Spellberg is also well worth reading, and locates the cloud in this silver lining: even after the intervention, over one-third of the patients were receiving broad spectrum gram negative active agents and almost half were still receiving broad spectrum anaerobic coverage. And yes, the investigators did exclude those patients who had complicating features (e.g. diabetes, recurrence, fasciitis, etc.) that may have justified such broad spectrum therapy. So even though the intervention was a partial success, challenges to optimizing therapy for SSTI remain.

Maryland report on hospital associated complications: Don't waste your time reading it

This week, NPR and the Washington Post ran stories on a new report on healthcare associated complications in Maryland. The report can be viewed here. Based on the results of the report, nine hospitals are required to pay penalties due to higher than average rates of complications. Eleven of the report's 49 indicators are infectious complications, such as infection related to central venous catheters. However, what is most important to know is that the source of the data for the report is administrative claims (ICD-9 codes which were developed for billing purposes). We've blogged before about how notoriously inaccurate these codes are for determining whether patients experienced healthcare associated infections. This is because case ascertainment is performed by abstractors with little medical training using case definitions that were not designed for surveillance purposes. Last year, Pennsylvania, the state with the most comprehensive mandatory reporting program for healthcare associated infections in the country, abandoned use of administrative claims data and required that all hospitals use CDC surveillance methodology. Particularly when hospitals are going to be punished by fines and bad publicity, valid methods must be used. I noted in the report that there were 431 cases of "moderate infectious," at a cost of over $6 million. What in the world is "moderate infectious"? I don't think you could find an infectious disease doctor anywhere who could tell you what that is because there is no such thing. Those of us who work in hospital epidemiology understand the need for public reporting because our society values transparency and accountability. We get it. But public reporting is a two-way street that requires a commitment on the part of public agencies to insure that the data generated are obtained via state-of-the-art methods and risk adjusted in order to produce the most valid reports for the public. In other words, it's about playing fairly.

Obit: Dr. Edwin D. Kilbourne

Dr. Kilbourne, source: NYT

Edwin Kilbourne MD, who was a graduate of Cornell Medical College and an accomplished influenza researcher, died earlier this week at the age of 90.  He was most widely known for his involvement in the swine flu epidemic of 1976. There is a nice obituary in today's NY Times.

Bad Science (part 2)

I just finished reading Ben Goldacre's book, Bad Science, and I highly recommend it. About a month ago, I posted about Dr. Goldacre, a British psychiatrist, and included his excellent, humorous video on the placebo effect. I liked it so much that I bought his book. He has an amazing ability to explain epidemiologic concepts and critical analysis to the general public. The book gives many interesting examples of problems with scientific papers and the problems with how the media translates them (often incorrectly).

Here's another video of him addressing a non-medical audience on evidence-based medicine. If only I could be this entertaining when I lecture!

Ben Goldacre Talks Bad Science from PopTech on Vimeo.