Wednesday, August 31, 2011

You can't B. cereus!

There was an exciting piece in the NY Times this weekend about the new “Microbe Hunters”, focusing on the wider availability of rapid whole genome sequencing, and characterization of complex communities of microorganisms (e.g. our microbiome). One part of the article referenced a case of rapidly fatal necrotizing pneumonia in a welder, and the suspicion that it may have been due to B. anthracis—possibly bioterror-related. The article breathlessly described the need for rapid species identification of the microbe:

“A patient had just died from what looked like inhalation anthrax. What should she do?
“I said, ‘I know precisely what to do,’ ” Dr. Musser said. “ ‘We just spent three hours talking about it.’ ”
The questions were: Was it anthrax? If so, was it a genetically engineered bioterrorism strain, or a strain that normally lives in the soil? How dangerous was it?
And the answers, Dr. Musser realized, could come very quickly from newly available technology that would allow investigators to determine the entire genome sequence of the suspect micro-organism.”

But as the case report reveals, it should have been clear that this organism wasn’t B. anthracis pretty quickly, just by looking at the agar plate. B. anthracis is non-hemolytic, and non-motile. B. cereus is both beta-hemolytic and motile. In fact, the lab involved identified it presumptively as B. cereus long before the whole genome sequencing was done. Furthermore, the association between B. cereus and necrotizing pneumonia among welders is well described, as is the presence of B. anthracis toxin genes in pathogenic B. cereus isolates. I’m not discounting the importance of genomic pathology—I’m just sayin’, you can still get a long way with traditional microbiological techniques (like looking at an agar plate).

Image courtesy of the CDC Public Health Image Library

Sunday, August 28, 2011

Why all the letters? STAR*ICU and VA studies agree!

Remember that April 2011 New England Journal of Medicine issue with results from two seemingly contradictory studies on MRSA control? Here was our take on both the VA and STAR*ICU studies, written the same week the studies were released. Apparently, some people chose to dust off their typewriters and comment the old-fashioned way. Those letters, and the authors’ responses, are now published. Aside from the last two letters, which make a good point about a flaw in the denominator of the VA study (the failure to remove patients not at risk for acquisition by virtue of already being colonized), all the letters start from the premise that these two studies have contradictory results.

As Charlie Huskins and his colleagues point out in their letter, this is a flawed premise. They point to Figure 3 of their paper to make this point—allow me to expand, since they were obviously working within some crazy word limit that bloggers are not bound by.

Below you’ll find Figure 3 from the STAR*ICU study, which graphs the number of MRSA and VRE “events” (new colonization or infection) during an extended baseline period and the intervention period, in both control and intervention units:

No differences between control and intervention units, and no significant difference from the baseline rates, right? Hold on a minute!! It really isn’t fair to compare these data to the VA data, since the VA study doesn’t include a concurrent control group and doesn’t include sufficient baseline data with which to perform a proper segmented regression analysis. So now let’s take all of that extraneous stuff out (you know, all that tedious extended baseline data and the control arm data—get rid of it!!!). Now the graph looks like this:

The trend line is mine, and demonstrates that MRSA and VRE events dropped by about a third in the intervention units. Since this measure incorporates both transmission and infection metrics, you’d predict it would land smack in the middle of the VA estimates for reduction in MRSA transmission (17-21% reduction) and infection (62% reduction). And it does!

So please stop claiming that the VA study and the STAR*ICU study don’t agree—they do agree, if you just ignore the baseline and control arm data. And as we’ve already learned, control groups are for losers.

Friday, August 26, 2011

IOM: 667 reasons why vaccines are generally safe

It's actually 667 pages.  The IOM has just released a report titled: "Adverse Effects of Vaccines: Evidence and Causality."  I've pasted a summary table (click to enlarge) of the major conclusions below, which you can also find, and read more easily, in the IOM Brief Report.  I hope this has an impact and convinces families that vaccines are safe, but somehow I get a feeling that it might have been better if instead of saying "favors rejection" for the vaccine link to autism, they might have said "nada" or "got nothing." I didn't realize this, but apparently the IOM has reviewed the safety of vaccines 11 times at the request of Congress since 1986. Well, should be a good read for my flight back from Seattle.


Full IOM report (here)

Wednesday, August 24, 2011

New infection prevention strategy: Send 'em to the big house

I guess this should come as no surprise, but it sure did shock me (and I'm not talking about the earthquake we had in Richmond yesterday). A congressman from Ohio has introduced a bill to criminalize infection control infractions in the VA healthcare system with punishments to include fines and up to 1 year in prison. We've blogged before about extreme infection prevention.

SHEA has rapidly responded by setting up training sessions for IPs and hospital epidemiologists to meet the new anticipated standards. Topics will include body combat and use of tasers. APIC is introducing its own line of handcuffs.

Tuesday, August 23, 2011

Antibiotic exposure a risk for pediatric MRSA

There is a nice case-control study in this month's Archives of Pediatric and Adolescent Medicine by Schneider-Lindner et al. in Quebec. Cases were kids 1-19 yo with outpatient MRSA and controls were matched on age and practice. The primary exposure was receipt of antibiotics between 30 and 180 days prior to MRSA infection. In the abstract, they even said they excluded antibiotic prescriptions within 30-days of MRSA infection to prevent protopathic bias. How cool is that! They said protopathic bias in the abstract! Oh, protopathic bias occurs when a treatment is unknowingly prescribed for an early manifestation of the disease, which has not yet been diagnosed.

They found that 53% of cases and 14% of controls had prior antibiotic exposure. So, 47% of MRSA cases in children occurred without recent antibiotic exposure. After multivariable analysis, the adjusted OR for exposure to any antibacterial was 3.5 (95% CI 2.6-4.8). As an example of a nice dose-response curve, the ORs increased with the number of prescriptions with a OR of 2.2, 3.3, 11.0 and 18.2 for 1, 2, 3, and more than 4 prescriptions, respectively.

I was going to write some additional comments in this space and even thought about writing something obnoxious like "Antibiotics Cause Resistance! Thank you Captain Obvious" But then I came across these nice comments in Reuters Health by honorary Canadian and famous co-blogger Dan, which I will post below.
  • "This just provides more evidence to support redoubling our efforts to decrease antibiotic use," Dr. Daniel J. Diekema, who was not involved in the new work, told Reuters Health.
  • "It (MRSA) remains a major public health problem, but the dramatic increase that we saw during the last decade seems to have leveled off in many areas and may be decreasing in some," said Diekema, an expert in infectious diseases at the University of Iowa in Iowa City.
  • "In general, only a minority of people who carry MRSA go on to become infected," Diekema explained.
  • "Observational studies like this really can't prove causality," said Diekema. But he added that it was biologically plausible that antibiotic use would fuel the growth of resistant bacteria.

Schneider-Lindner et al. Arch Pediatr Adolesc Med, August 1, 2011

Reuter's Health, August 11, 2011

Saturday, August 20, 2011

Contagion - September 9th!!

I know Mike posted about this a month ago, but I saw an ad of the upcoming movie Contagion while watching Cubs/Cards and they've released the opening date. Mark your calendars. If you haven't seen 'Rise of the Planet of the Apes', it's pretty clear that the next "Apes" movie will have a similar global pandemic theme.

Friday, August 19, 2011

Dog Days of Winter?

The Dawg Pound in Cleveland Browns Stadium

As the 'Dog Days' of summer come to an end and Cub's fans everywhere enter into their official waiting 'til next year period, it's time to look forward to those crisp winter days with clean cool breezes and the cheers from college and NFL football fans filling the air. Well, that is, unless you live in Cleveland and Detroit. These cities share so much in common  - the devastating destruction of their industrial core and their long-suffering NFL fans (the Browns and Lions play each other tonight). Now they share something else in common and it isn't pretty - airborne dog feces.  Seriously.

A new study in Applied Environmental Microbiology by a group at University of Colorado, Boulder, aimed to characterize the microbes circulating in urban environments, which could trigger asthma and allergies, by analyzing the air in the summer and winter at four locations in the Great Lakes region: Chicago, Cleveland, Detroit and... Mayville, Wisconsin. I guess Milwaukee took a pass? Smart thinking. Their primary finding was that two cities, Detroit and Cleveland, had significant quantities of fecal bacteria in their atmosphere with dog feces being the most likely source, particularly in the winter. Good news!

In an an accompany CU press release, first author Robert Bowers said that "in the summer, airborne bacteria come from many sources including soil, dust, leaf surfaces, lakes and oceans, but in the winter, as leaves drop and snow covers the ground, the influence that these environments have as sources also goes down. It is during this season that the airborne communities appeared to be more influenced by dog feces than the other sources tested in the experiment." Well, now we know the real reason why the Cleveland NFL team is called the Browns. If you've ever been in the Dawg Pound, you wouldn't be surprised that there was a lot of fecal bacteria floating around. I'm just surprised it's from dogs and not Dawgs.

Thursday, August 18, 2011

Human-to-coral transmission: Damn you, Serratia!

Some of you may be enjoying a relaxing coastal summer vacation, snorkeling in breathtaking coral reefs. You might think that nasty nosocomial pathogens would never follow you to such an idyllic paradise. Well, you’d be wrong! Turns out that Serratia marcescens is responsible for a disease that is killing elkhorn coral all over the Caribbean, and that the responsible strain has been isolated both from the diseased coral and from human waste.

We all know S. marcescens as a cunning nosocomial opportunist, one that is often the culprit when outbreaks are linked to contaminated intravenous preparations, soaps, and disinfectants. Now we have circumstantial evidence supporting S. marcescens as a “reverse zoonosis”, here.

Rising plague, falling plague?

In a continuation of the EIN string I recently blogged about, a commenter discussed the success of an MRSA “search and destroy” program they implemented at their hospital. I thought the response by Brad Spellberg (ID doc extraordinaire, and author of “Rising Plague”) was right on target (and consistent with one of the points Eli and I tried to make in our JAMA editorial):
"With respect to the comment, “With this aggressive search and destroy program, we have had a drop in our MRSA rates for the past 4 years in a row with a marked decline in nosocomial transmissions”, I’d advise caution in interpretation.

I think many healthcare systems are seeing declines in MRSA rates nosocomially, including sites that haven’t done much different. Furthermore, we and others I’ve talked to have been seeing dramatic declines in community MRSA rates as well. Let’s not forget, we have no idea why MRSA emerged into the community, why USA300 took over, and where the related phage 80/81 strain went in 1961 and where it hid for nearly 40 years before re-emerging. Why should we be surprised that it has decided to move on now? Let us not underestimate the impact of changes in bacterial ecology that are not necessarily related to things we’ve done."

Tuesday, August 16, 2011

The “horizontalists”

Contact precautions, blah, blah, blah. Regular readers know that this is one of the topics we revisit often. Yet in my decade as a hospital epidemiologist, I never suggested we stray from the current CDC guidance on use of CP in healthcare settings. Why? For one thing, I was a VA hospital epidemiologist--but VA or not, it is a real challenge to convince colleagues and hospital administrators to make such a major practice change, especially if it is not consistent with existing authoritative guidance. No one wants to be an outlier on an issue like this, perhaps fearing not only increased infection rates but also repercussions from JCAHO or other surveyors. Or maybe I just don’t have the courage of my convictions (one of those convictions being that “horizontal” population-based approaches are more effective overall, and in the long run, than are pathogen-based “vertical” approaches). Not everyone has been so hesitant to put this theory to the test, however. Below are excerpts from a current thread on our Emerging Infections Network listserve:
We are looking into getting rid of isolation gowns, exclusively for MRSA and VRE in a relatively small teaching hospital. We are planning on focusing more on handwashing and glove use when appropriate, as well as monitoring for any changes in the rate of HAI. I have heard through the grapevine that there are other institutions that gave up on MRSA and VRE contact isolation. At this point we are not using active surveillance with swabs, but we do isolate MRSA and VRE based on finding them in any clinical cultures or based on historical data from previous admissions, which does not make much sense to me. I am interested to hear opinions from the forum, especially from people who went through a similar process. What are the barriers that you encountered? What are people thinking of the 2 papers that came out in April in NEJM? (neither of which apply to what we are doing now, since we are not swabbing noses regularly, but still....we are going completely opposite way of what the VA did).

Date: Mon 15 Aug 2011 11:37
We do not isolate MRSA or VRE. Our area has an exceptionally high incidence on CA-MRSA, and the Dept of Public Health has endorsed this approach as well. I think, when you examine any "bundled" approach, hand hygiene is the key factor, tho often it is difficult to break out. I am as concerned about transmission from the patients we don't know are colonized as much as those we know about, so support a "universal" approach.
Date: Mon 15 Aug 2011 12:53
Hi - At [ ] Medical Center we are 9 months into our change to the policy you describe emphasizing vigorous adherence to standard precautions and eliminating contact precautions for VRE and MRSA. We are currently analyzing the data but do not have any change in infection rates to report. We will also be looking at bed flow and additional quality of care factors in respect to the change.

My own opinion on the discrepancies seen in the literature in regards to the topic are that where hand hygiene improvements were possible interventions such as the VA study make an impact but places such as the Swiss study released a few years ago where hand hygiene was in place there is no or minimal added benefit from applying the contact precautions.

I like our current approach where the emphasis is on preventing transmission in all patients regardless of their known colonization/ infection status as opposed to raising the alarm and isolating a subset of the population who may or may not be the true culprits in terms of current/active shedding of resistant organisms.

Sunday, August 14, 2011

As if flying weren't miserable enough...

The CDC is urging the 50 passengers on this recent Delta flight to contact them regarding potential rabies risk from a bat flying around the plane (the flight left Madison, WI, and returned there shortly after takeoff, after the bat made several forays through the cabin and was finally trapped in the airplane bathroom).

I have only two comments. First, the rabies risk, at least from the video footage, seems close to zero. The bat didn’t interrupt its flight long enough to scratch or bite anyone. Second, that’s a pretty big bat! If the plane was domestic only, it seems most likely to have been a “big brown”. Of the 45 documented human rabies cases in the U.S. since 1995, only one was traced to a big brown bat (most are associated with silver-haired or eastern pipistrelle bats). Given the size, it’s pretty disappointing that it couldn’t be captured for testing (it was trapped in a tiny airplane lavatory!). Detaining the bat for further analysis would have simplified the contact counseling greatly.

I’m sure all affected passengers will be offered free drinks on their next Delta flight (provided they aren’t hydrophobic).

Friday, August 12, 2011

Quote of the day

Photo: Iowa Medical Society
There's an article in today's Baltimore Sun on influenza vaccination of healthcare workers. What a piece of work! Here's a quote from the chief medical officer of a large health system in the Maryland/DC area:
 "If you look at data on how many people die in this country from influenza, it overwhelms all other hospital-acquired infections in numbers, and you couple that with the voluntary vaccination programs that weren't successful in getting 98 to 100 percent of employees, and this becomes an argument for a mandatory policy."

Let's examine the data. According to CDC, it is estimated that there are about 100,000 deaths due to hospital-acquired infections in the US. Also, according to CDC, on average, 25,000 persons in the US die from influenza each year. And it's important to consider that the vast majority of influenza cases are not acquired in the hospital. So what in the world is the CMO talking about? Most intelligent people who read this article would conclude that influenza kills more inpatients than all other hospital-acquired infections, yet that is absurd. Inside and outside the hospital, flu kills one-fourth the number of patients who die from non-flu HAIs.

I won't rehash my arguments about mandatory influenza vaccination; you can read them here. But even if you're a believer in the get-vaccinated-or-get fired school of thought, I think you have to admit that the impact of such programs pales in comparison to those aimed at reducing CLABSIs, for example. So articles like this one in the Baltimore Sun simply misinform the public and divert attention from bigger, more important problems.

Economicks is hard!

I had the privilege of training in hospital epidemiology under Dr. Richard Wenzel, and alongside a number of really smart people (including fellow blogger Mike Edmond). We put a lot of time and energy into estimating the impact of HAIs on costs, lengths of hospital stay (LOS), and mortality…and our approach was simple and intuitive. If our HAI cases had a mean cost/LOS/mortality of x, and matched controls had mean cost/LOS/mortality of y, then the attributable cost/LOS/mortality must be x minus y. Right?

Yes, I’m oversimplifying, and I will give us credit for understanding that it was a little more complicated than that. However, at that time we were still trying to convince people that HAIs actually killed people, and that the damage they did was above and beyond that due to the patient’s underlying illness. So if our estimates were on the high side, it seemed OK (at least to me), since the main purpose was to jar people out of their complacency and increase resources for prevention.

The climate has changed. We know a lot more about the complexity of estimating the costs of HAIs (two excellent sources on this are here and here), and we’ve (at long last) succeeded in attracting needed attention to HAI prevention (from the public, from legislators, from the media, even from our hospital administrators!). So it now behooves us to “take it up a notch”, as advocated by Nicholas Graves and colleagues in a recent letter to the editor at ICHE (with response). You can read these at your leisure, but I want to highlight this section of their CID article, which I think is on target:

"The 'HAI costs a lot' approach to influencing decision making has served the infection control community well…..The time has arrived, however, for the methodological advances that have been achieved in this area to be implemented by researchers. Complete economic evaluations that include changes to all costs and health benefits should be performed...

The information used to update these studies should be of high quality and bias free. Inexorable growth in health care costs is forcing decision makers to respond to scarcity and work toward extracting greater value from health care resources….The time when reliable economic arguments will be paramount for obtaining extra resources—and even retaining existing ones—is close. Those working toward reducing the number of HAIs should craft valid economic arguments on the basis of sound methods and use them to build strong and cost-effective infection control programs"

Wednesday, August 10, 2011

Central line + positive blood culture = CLABSI (not!)

There's a thoughtful commentary in a recent issue of Clinical Infectious Diseases by Tom Fraser and Steve Gordon at Cleveland Clinic on problems related to CDC's central line associated bloodstream infection (CLABSI) case definition. We've blogged about this before. The definition is old and was designed to maximize sensitivity long before anyone thought about public reporting. But the issues of poor specificity of this definition are haunting many of us, particularly those who work at hospitals with cancer centers. Unfortunately, neutropenic cancer patients not uncommonly have translocation of enteric flora across their intestinal mucosa and the resulting bloodstream infection in the presence of a central line forces us to label these as CLABSIs, even though these infections are not at all related to the central line. Ten years ago no one cared about this surveillance technicality. Now, in the era of public reporting this is a big problem. In fact, nearly every "CLABSI" in the medical ICU of my hospital falls into this category. Fraser and Gordon show us how this is handled at their hospital with a modification to the CDC definition that is used for internal purposes. Hopefully relief is on the way. CDC is very interested in this issue and has assembled a committee that is actively evaluating the issue.

Open Source ARIC Journal: Now Open!

As we mentioned back in June, there's a new open-source BMC journal titled - Antimicrobial Resistance and Infection Control (ARIC).  The website for submissions is NOW active. Per Andreas Voss, the Editor-in-Chief, manuscripts are being accepted and the "under construction" sign will be removed after the first paper is published. In addition to Andreas, Jan Kluytmans is the Deputy Editor and Didier Pittet is the Executive Editor, so this will be an excellent addition to our field and the benefits of having an open-source option can't be over emphasized. Submit your manuscripts here and read more about what types of papers they are looking for here.

Journal website:

Monday, August 8, 2011

No more sleepy doctors?

Photo: Sleepless and Tired
Yesterday's New York Times Magazine had an article on the new ACGME residency work hour rules written by a pediatric cardiologist. I think it presents a balanced view of the the topic and it interests me for several reasons. I recall several scary episodes from my own sleep-deprived residency days, including giving nurses verbal orders in my sleep, but I was luckier than one of my colleagues who demolished his car after a night on call. As a hospital epidemiologist, my interest in the new rules revolves around whether there will be any impact on medical errors, which the article points out is still open for debate. As a medical educator, I'm also interested in the impact on medical education, which the article does not address. Will the decreased hours and the associated decrease in clinical experience lead to less competent doctors? And the rules have also impacted the work environment in the hospital, a topic I addressed in an essay published last year. While I favor the rules and strongly support having well-rested doctors, I do worry about the adverse unintended consequences.

MRSA in Decline: England Edition

Don't know what I want
But I know how to get it
I wanna destroy passerby

-Sex Pistols "MRSA? in the UK"

MRSA rates have just reached their lowest levels in recorded history. Per a BBC report, there were 97 cases in the entire NHS in June, which represents the first time rates have been below 100. 25 hospitals had no MRSA cases in the month. C. difficile cases are also falling, so the decline is likely due to an overall emphasis on infection prevention including hand hygiene, which would impact both infections. Good news, overall.

BBC report
Guardian report

Friday, August 5, 2011

Architectural yogurt for our hospitals?

Professor Jessica Green is an engineer and ecologist from the University of Oregon and the founding director of the Biology and the Built Environment (BioBE) Center that bridges biology and architecture. In this recent TED video she describes a study where they compared the diversity and origin of bacteria in hospitals to the outdoors. Her conclusions are intriguing in an intermediate outcome sense.  Enjoy.

Tuesday, August 2, 2011

Contact precautions, and why I hate them, entry number next

Regular readers of this blog know that we’ve raised many questions about contact precautions (CP). We have very few arrows in our quiver to fight multiple-drug resistant organisms (MDROs). CP is one of them. So naturally it has become infection prevention dogma that CP is necessary to control MDRO spread. Never mind that the effectiveness of CP has really only been demonstrated in outbreak settings, that adherence to CP is often terrible, and that CP likely has several nasty unintended consequences that can harm patients. The bottom line? We desperately need more research, both to address the effectiveness of CP at preventing pathogen transmission, and to address the potential unintended consequences of widespread application of CP.

Regarding the latter (unintended consequences), we have two recent additions to the literature courtesy of Eli and his homeys back in Maryland. The first study, led by Dan Morgan, examines the relationship between CP and adherence to several quality-of-care process measures (e.g. SCIP, pneumonia, CHF, acute MI), and the second study, led by Hannah Day, examines the relationship between CP and depression among acute care inpatients.

I have an obvious conflict of interest and will therefore not critique either study. Instead I will leave it to you, dear reader, to assess their quality and to leave any comments, positive or negative, that you wish.

Monday, August 1, 2011

Things that make you go "hmmm"...

I’ve been in an undisclosed location for the past week or so. Hint—if I were to hop on the above watercraft and drive directly across the above body of water, I’d be in the city that in the Potawatomi language translates (roughly) as “fine land”.

In among my beach reading I ran across this article, about a recent biowarfare exercise:

“AVI BioPharma, Inc., and the Naval Research Center recently announced the successful completion of a rapid-response exercise conducted by the Joint Project Manager Transformational Medical Technologies…..In a total of 18 days, AVI conceived, designed and manufactured two novel RNA-based drug candidates, one against a Gram negative bacterial target and one against a viral target.”

Eighteen days to conceive, design and manufacture a drug active against a Gram negative pathogen! Meanwhile, the only option for treatment of many multiple-drug resistant Gram negative infections is a drug that’s over 50 years old.