Tuesday, July 29, 2014

Ebola Hemorrhagic Fever: A Primer

The Ebola outbreak in West Africa appears ever more worrisome. Since it is likely that a sick traveler will arrive in the United States and since most physicians and infection preventionists have never dealt with the disease, I thought it would be good to put together a quick review.

Epidemiology
  • The current outbreak in Guinea, Liberia, and Sierra Leone is the largest ever recorded, with approximately 1200 cases to date, and ~60% mortality.
  • The natural reservoir of the virus (a filovirus) is suspected to be bats.
  • Transmission occurs via contact with infected human body fluids (blood, saliva, vomitus, stool, semen, breast milk, and tears).
  • Nosocomial transmission is a key driver of outbreaks.
  • Transmission has not been demonstrated from individuals who are in the asymptomatic incubation period.

Clinical
  • The incubation period is 2-21 days (usually 5-7 days).
  • The illness is characterized by abrupt onset of fever, chills, myalgias and malaise. This is followed by GI symptoms (nausea, vomiting, diarrhea and abdominal pain), cough, headache, and conjunctival hemorrhages. 
  • Hemorrhagic symptoms usually occur at the peak of illness and include maculopapular rash, petechiae, bruising, and bleeding from venipuncture sites. Gross bleeding from the GI and GU tracts is usually only seen in dying patients.
  • The late stage of disease is manifested by shock, capillary leak syndrome, seizures, delerium, coma, bleeding and anuria.
  • Laboratory findings include leukopenia, thrombocytopenia, elevated transaminases, proteinuria, and markers of DIC. 
  • In survivors, the convalescent phase is long.
  • Ebola Fever should be suspected in a patient with a history of travel to an outbreak area who has fever, myalgias, and two of the following (rash, nosebleed, hematemesis, hemoptysis, hematochezia).

Diagnostic Testing 
  • In the US, all testing is performed by public health laboratories.
  • Available testing includes antibody testing (ELISA), PCR and viral culture.

Treatment
  • No specific antiviral therapy is currently available.
  • Treatment is focused on supportive care.
  • Corticosteroids, nonsteroidal anti-inflammatory drugs, and aspirin are contraindicated.

Infection Control and Prevention (CDC guidance here)
  • Contact and airborne precautions are indicated for suspected and confirmed cases.
  • Eye protection (goggles or face shield) is specifically recommended.
  • Some experts also recommend double gloving and shoe covers.
  • Careful removal of PPE followed by hand washing is imperative.
  • At this time, there is no available vaccine or chemoprophylaxis.

Resources:

Photo: Frederick Murphy, CDC.

Wednesday, July 23, 2014

A compendium of awesomeness

Posting has been light this month, for several good reasons. My own schedule has been full with seeing patients, attending HICPAC, and most recently riding a bike across northwest Iowa during the first couple days of RAGBRAI with my mom (the route this year went through her hometown of Hull, Iowa). The photo above was taken on Sunday during a stop in beautiful Boyden, Iowa

I’m back at work now, and marveling at the complete online release of the SHEA/IDSA Compendium of Strategies to Prevent Healthcare Associate Infections. The Google tells me that a compendium is “a collection of concise but detailed information about a particular subject”. This compendium is about HAI prevention, and it is required reading for anyone in the field. I could go on at length about the work that went into this practical guide to prevention, but suffice it to say that it makes me very proud to be a SHEA member. For those not yet familiar with the compendium, I’d suggest starting with this introduction, which describes the approach, the key contributors and the partner and sponsoring societies. Then read the executive summary, and the infection prevention viewpoint. Finally, refer to the individual documents for more detailed information. They make great beach reading!

Thursday, July 10, 2014

THIS...is what we need more of

A little late on this post, but summer.

There's a new randomized trial published in JAMA that evaluates the efficacy of post-cholecystectomy antibiotics in patients presenting with mild/moderate acute calculous cholecystitis. Upon diagnosis, all patient received amoxicillin+clavulanic acid three times a day pre-operatively and once during surgery. This open-label trial compared patients randomized to 5 days of post-operative antibiotics with the same antibiotic regimen vs. no post-operative antibiotics.  Patients were followed up to four weeks post-operatively for SSI and other infections. In the 414 patients, the infection rate was 15% (31/207) in the post-operative antibiotic group and 17% (35/207) in the no-antibiotic group, in the intention-to-treat analysis. The absolute risk difference was small (+/- 2.0%) and the 95% CI for the difference included zero for all key outcomes in the intention-to-treat analysis including superficial, deep and organ space infections. (Table 3 below)

The study appears to have high internal validity and randomization looks adequate. However, the lack of placebo and a relatively large non-inferiority outcome threshold (11%) are potential limitations. Of course, the study was also limited to amox-clav and perhaps some would favor testing other antibiotic regimens. However, the lack of true difference will hopefully lead to further validation studies or adoption of a no post-operative antibiotic recommendation for this surgical procedure. This study and hopefully more like it are exactly what we need in order to reduce antibiotic exposure in hospitals and subsequent selection of antimicrobial resistant pathogens, including C. difficile. It's great to see important antimicrobial stewardship questions asked and answered.


Tuesday, July 8, 2014

A blast from the past

Don’t you hate it when you’re rooting through your storage closet, looking for some old high school yearbooks, and you stumble across a few vials of smallpox you forgot to destroy? Yes, smallpox—declared eradicated 34 years ago—is serious. But there is irony here. Recall the year 2002, when our political leaders used the threat of “hostile groups or governments” in order to implement a smallpox vaccination campaign (one that failed miserably, achieving vaccination of only 10% of its stated target). Alas, Saddam didn’t have smallpox, but he might have stood a chance to procure it if he had only befriended the night janitor at a certain lab in Bethesda.

I’ll use this opportunity to highlight the 2002 NY Times editorial that called out Mike and his hospital for refusing to implement this misguided vaccine campaign. In retrospect, quite a badge of honor to have been deemed “deplorable” in the paper-of-record, for making a reasoned decision to protect patient and healthcare worker safety.

Thursday, July 3, 2014

...at least she didn't die of MRSA

For the past six months our group at Iowa has been collaborating with colleagues at the University of Utah on a project for CDC. We are tasked with measuring the burden of MDRO using systematic reviews to inform economic models that will project MDRO incidence and attributable cost over the next 20 years. We are studying pathogens like C. difficile, VRE, MRSA, ESBL-GNR and CRE. It's a tall order, but we expect that CDC and others will use these estimates to guide funding for research and prevention efforts. Since bacterial pathogen research is so widely underfunded compared to their burden of disease, these new estimates can only help.

But, it has occurred to me that the planned approach of estimating the burden of disease using pathogens typically categorized as MDRO, such as CRE and MRSA will result in serious underestimates of the bacterial pathogen burden and lead to perpetuating the chronic underfunding of our research and prevention efforts. A simple way of demonstrating the impact of neglecting susceptible bacteria is to focus on S. aureus. One widely cited estimate of yearly MRSA mortality burden is 18,650 in-hospital deaths. Ignoring secular trends and community deaths, while assuming 50% of S. aureus infections in the US are MRSA (and thus 50% are MSSA), we might estimate that S. aureus kills 37,300 people annual in the US. This would place S. aureus (one bacteria!) ahead of traffic deaths and rank it as the #11 cause of death in the US (see table below). Imagine if we included "susceptible" (and resistant) bacteria like E coli, Klebsiella and Streptococcus in a total bacterial burden estimate!

For those that will argue that we have effective antibiotics for MSSA, so that it's unimportant, I offer several counterpoints. First, people die of "susceptible" bacteria (18,650 MSSA!) and we don't fund HIV research based on mortality burden for only protease inhibitor resistant strains. Second, even strains we call susceptible are actually resistant to numerous classes of antibiotics - most MSSA is actually PRSA and try treating enterococcus with a cephalosporin. Third, by ignoring susceptible strain burden, we underinvest in strategies that could treat or prevent all infections, not just arbitrarily defined resistant ones. For example, S. aureus vaccines could prevent both MSSA and MRSA infections. If NIH (or CDC or ECDC) uses only MRSA burden to guide funding of S. aureus vaccine research, they would underfund by 50%.

You get my point, but I will leave you with my final reason for recommending inclusion of "susceptible" strains when measuring burden of disease for bacterial pathogens. Imagine if your aunt is very sick with an MSSA prosthetic hip infection in the ICU. And then imagine if the doctor comes to inform your family that she is very sad that your aunt has passed away, but adds... "at least it wasn't MRSA." Does that make you feel any better?


beer image: source

Tuesday, July 1, 2014

Do you have a question?

IDWeek abstract dispositions were just emailed last week. Hopefully you received good news and have already started planning your trip to Philadelphia! IDweek discounted registration closes July 25th.

For those also attending SHEA2015 in Orlando, this will be the first SHEA meeting in three years where we will be accepting abstracts (kinda like the old days but with competitions, voting and awards). So get busy making science - abstract submission closes January 16, 2015.

Whether you are attending IDWeek, SHEA or both meetings, I thought a quick review of Q&A etiquette was in order. I've pasted an algorithm to follow when you're thinking of asking a question at either meeting. These questions are particularly important to follow if you're thinking about asking a question during a University of Iowa student presentation. Thanks!


source: this diagram has been all over twitter the past two months. I have no idea who to thank or where to give attribution. If anyone knows, please comment and I will update the post. 

Saturday, June 28, 2014

What the HAC?!

The University of Wisconsin (UW) Hospital is an excellent institution with a stellar infection prevention program. In fact, last year they won the prestigious U.S. Department of Health and Human Services (HHS) Partnership in Prevention Award, which recognizes “prevention leaders in the U.S…who have achieved wide-scale reduction and progress toward elimination of targeted health care associated infections.” Sadly, this achievement may not be enough to keep HHS from levying financial penalties against UW for high infection rates

Yes, the Hospital Acquired Condition (HAC) scores have come out, and have been generating a fair bit of media coverage, focused on those hospitals most likely to face financial penalties. Funny thing, though—the hospitals most likely to lose money under this program share a lot of characteristics:
“who is getting penalized? Large, urban, public, teaching hospitals in the Northeast with lots of poor patients. Who is not getting penalized? Small, rural, for-profit hospitals in the South. Here are the data from the multivariable model: The chances that a large, urban, public, major teaching hospital that has lots of poor patients (i.e. top quartile of DSH Index) will get the HAC penalty? 62%. The chances that a small, rural, for-profit, non-teaching hospital in the south with very few poor patients will get the penalty? 9%.”
Interesting. Explanations for these findings include: (1) small size, rural location, southern region and for-profit status magically translate to higher-quality, safer care, or (2) this HAC metric is bullshit, as it obviously doesn’t adequately control for myriad variables that are associated with the score but that are not indicators of quality and safety. What variables? Intensity and accuracy of surveillance, and variation in infection risk of the different patient populations, for starters.

I can overlook bullshit when it brings more attention (and resources) to the critical task of infection prevention. Unfortunately, this particular form of bullshit does the opposite (unfairly punishing already cash-strapped hospitals with financial penalties). As others have pointed out, the current HAC metric is well-intentioned but obviously flawed, and in desperate need of fixing.