Sunday, September 30, 2012

Who will win the all-important Lyme conspiracy theorist vote?

I have no idea, but the Romney-Ryan campaign seems to have the advantage. Slate and the Weekly Standard describe the details of a direct mail campaign in Virginia, courting the votes of those who believe that there exists a conspiracy to underdiagnose and undertreat Lyme Disease. Here’s an excerpt from the mailer:
Encourage increased options for treatment of Lyme Disease and provide local physicians with protection from lawsuits to ensure they can treat the disease with the aggressive antibiotics that are required.
Translation: we’re in favor of protecting doctors who commit malpractice and place patients’ lives at risk by prescribing weeks of unnecessary antibiotic therapy for a disease that their patients do not have.

During my first few years of infectious diseases practice, I was asked to consult on a young mother admitted to the ICU for severe sepsis due to drug-resistant Pseudomonas, acquired by virtue of the weeks of intravenous ceftriaxone she’d been prescribed for a misdiagnosis of “chronic Lyme”. Her actual diagnosis was post-partum depression, for which she was eventually treated successfully, after barely surviving her hospitalization. Others haven’t been so lucky.

Wednesday, September 26, 2012

Reducing preventable harm, fraternity edition

Don't do this

It could cause death from alcohol poisoning. Also, it is generally unhygienic, and I suspect that it wreaks havoc on the colonic microbiome.

Tuesday, September 25, 2012

Guest Post: A "Hybrid" Surveillance approach for SSI

Dr. Connie Savor Price has been co-project director and PI on a 2009 AHRQ ACTION contract charged with improving the measurement of surgical site infection risk stratification and outcome detection. The final report has just been published online and she was kind enough to stop by our humble blog to briefly describe the project.

With pressure on infection control programs to expand surveillance for public reporting and pay-for -performance, increasing surveillance efficiency without sacrificing data validity creates a conundrum. Purely automated systems for surgical site infection (SSI) surveillance have been developed and utilized, but are not validated or generalizable for these purposes.

In this report, we describe development of "hybrid" surveillance approach using highly sensitive electronic algorithms for detection of SSI targeted for subsequent human-adjudication. Electronic algorithms to detect deep and organ-space SSI after coronary artery bypass grafting, total hip and knee arthroplasties, and herniorrhaphies were created using a sample of nationwide Veterans Affairs Surgical Quality Improvement Program data (VASQIP). The algorithms were tested against VASQIP data, and then assessed for generalization using data from hospitals from three different, external (non-VA) healthcare systems.

Although all algorithms performed reasonably well at identifying deep and organ-space SSI among the VASQIP test data set, performance was variable when tested against data from the outside systems. As one would expect, the observed variation was primarily due to differences in the data collected and stored electronically in each system. While not surprising, perhaps some are disappointed that this research did not produce a universally applicable surveillance tool for "out-of-the-box" utility for all infection control programs. But just wait. As meaningful use incentives help us move toward interoperable electronic health records throughout the United States, this surveillance strategy will hold promise as a reliable tool for detecting potential surgical site infection.

Monday, September 24, 2012

Man who first synthesized AZT, d4T and ddC dies at 93

Many of us probably have never heard of Jerome Horwitz, but there are few who have done as much for public health and infection prevention as he has. Dr. Horwitz synthesized the nucleoside analog reverse transcriptase inhibitors, AZT, d4t and ddC back in the 1960's as potential chemotherapeutic agents. They were pulled off the shelves in the 1980's and 1990's and proved to be some of the first successful antivirals effective against HIV and served as a model for future discoveries. Sadly, he never obtained patents on these agents and thus, someone else profited from his genius and efforts. To read more about Dr. Horwitz, please read the obituary in the NYT.

A couple errors are present in the current obit: Dr. Horwitz discovered zalcitabine (ddC) and not didanosine (ddI) and it is stuvadine (d4T) and not "stauvidine" that he synthesized.

Friday, September 21, 2012

The depredations of the Staphylococcus

From: Public Health Image Library
“Among the more chastening chapters in the annals of microbiological research is the story of our apparently dismal failure to control the depredations of the staphylococcus.”
The above quote, by Canadian microbiologist Claude Dolman, remains as true today as when he wrote it in 1955. Each time I attend on our busy ID consult service, I’m astonished again at how very nasty, and how very common, is S. aureus. Earlier this week we saw a patient with a confusing clinical presentation (confusing to me, anyway). At the end of the day, as we were going back over plausible etiologies for his symptoms, I said, “it’ll probably end up being just another presentation of invasive S. aureus disease”. As I was saying those words, his admission blood cultures were turning positive for….yes, S. aureus (in this case, methicillin-susceptible S. aureus). At any given time, I’d say about half the patients on our consult service have invasive S. aureus disease (evenly divided between community-acquired and “community-onset healthcare-associated”).

If you type “aureus” into the IDWeek online program planner, you’ll get 170 matches. That’s a lot of learnin’ you could do about S. aureus epidemiology, diagnosis, treatment and prevention! So if you haven’t yet signed up, please join us next month in San Diego.

Tuesday, September 18, 2012

The nation is talking....about KPCs!

Later today our colleague and fellow-blogger Eli will be one of the experts interviewed on NPRs Talk of the Nation. He will be discussing “the next steps in the fight against superbugs”. According to the preview, this segment will be aired during the second hour of the show. Tune in to hear Eli talk to the nation, revealing for the first time ever what the letters “KPC” really mean. If you miss it live, you can listen here once the show has aired.

Monday, September 17, 2012

Nothing to see here, please move along

It's been a quiet week out here on the edge of the blogging prairie. Some of us are recertifying, some are in the middle of huge grant deadlines and some are chairing a giant meeting planning committee with the meeting imminent. But, we still think about you every second and we miss providing you with up-to-date infection prevention information...

In the interim, we have created a little poll off to the right, which you can use to let us know how you like to read or follow the blog.  Vote early and often.

From the nothing to see here column: We've heard new reports that the NIH KPC outbreak that was halted by whole-genome sequencing is back. On September 7th there was a new case of the KPC strain, the first since January and 19th overall. The blood stream infection resulted in the unfortunate death of boy from Minnesota, the seventh fatality attributable to the strain.

NOW SEE THIS: Registration for ScienceOnline2013 is now officially open. It's the seventh annual un-conference exploring science on the Web and takes place Jan. 30-Feb. 2, 2013, in Raleigh, NC. Registration for the first round of 100 slots is closed for today, but there are two more opportunities to register: Thursday, Sept 20, 2012 at 2:00 PM (EDT) and Friday, Sept 21, 2012 at 11:00 PM (EDT). By rumor I heard that these sessions last only minutes, so log on near those start times and keep refreshing your browser. All seems pretty exciting.

Thursday, September 13, 2012

Rise of Predatory Open-Access Publishers: Authors Beware!

One of my mentees was recently asked to join the editorial board of a journal we've never heard of and others have been asked to submit papers and become editors for special issues for brand new journals. My advice is always to steer clear of these journals. It seems our experience is not unique.  In a recent Q&A for the Chronicle of Higher Education, Carl Elliot describes the rise of predatory publishers, how they are interfering with promotion and tenure and why we must protect junior faculty from them. Definitely worth a read...

image source: wikipedia (NJR ZA)

Wednesday, September 12, 2012

Learn your mec-A-B-C's!

Remember the divergent mecA homologue that we blogged about last year, the one not detected by conventional PCR tests? This livestock-associated strain was described in Lancet and AAC as causing human disease in the UK and Denmark (and now France, and probably elsewhere).

Assuming that bacteria will continue to evolve, and that we will continue to track their spread, new mecA homologues will undoubtedly be discovered. Recognizing this, the IWG-SCC (International Working Group on the Classification of Staphylococcal Cassette Chromosome Elements—a shadowy international cabal obsessed with classifying staphylococcal chromosomal elements) has a short but lucid commentary on how these novel mecA homologues should be reported. As outlined in the table below (from the paper), the guideline suggests using letters and numbers to distinguish new homologues based upon the % nucleotide sequence identity compared with the prototype mecA strain (N315). Using this nomenclature, the strain we previously discussed (LGA251) is now mecC.

Monday, September 10, 2012

Universal Influenza Vaccine Update: ICAAC 2012

Donna Ambrosino and Zachary Shriver (both from Visterra) discuss their monoclonal antibody approach. Wendy Keitel, originally scheduled, unfortunately missed the session.

By the way, can you tell by my last 3 posts that I wish I was at ICAAC?

Seasonal Flu Vaccine and Pandemic Severity: ICAAC 2012

Talk and discussion from Dr. Danuta Skowronski, BC Center for Disease Control, Vancouver, BC, Canada. Did receipt of seasonal flu vaccine increase the risk of pandemic virus infection?

More videos will be posted during the conference on MicrobeWorld's YouTube Channel

Helen Branswell, Canadian Press, covered this topic in an excellent article yesterday.

ICAAC 2012: Top 10 Papers

If you can't be at ICAAC, this is the next best thing.  Why? Because we love you. Special thanks to Andreas Voss and Loreen Herwaldt. Note: There are at least 60 papers listed. Like all infection prevention folks, they give you a lot for your money.

Friday, September 7, 2012

HAI prevalence and positive predictive value

Eli’s excellent post about problems associated with use of ICD-9 codes to assess HAI burden can be extended to other surveillance approaches. That PPV erodes as disease prevalence drops (for HAIs, presumably through better prevention), is Diagnostics 101. So let’s take the example of laboratory-based tracking of C. difficile infection (CDI). The figure below is from a meta-analysis of CDI diagnostics published last year in Clinical Infectious Diseases. In most hospitals using PCR, positive test rates approach 15-20%. In these settings, the PPV is good (>80%). If a hospital or region were somehow able to push their CDI prevalence to below 5% in the tested population, however, PPV falls below 50% and gets worse as prevalence drops further. 

This is a good problem to have, generally speaking, but it does present problems for surveillance approaches as HAI rates drop (and also provides a reality check regarding “zero” targets, which are only achievable using subjective definitions that allow for human judgment/adjudication).

P.S. As a corollary, remember that when you extend CDI testing to patients with a low pre-test probability of disease (e.g. by repeat testing of those who initially test negative, by testing formed stool, or by performing "tests of cure"), you are both wasting resources and reducing PPV.  

We can't predict HAI with ICD-9 codes and it's only going to get worse

I'm getting ready for a chat with a reporter concerned with issues surrounding HAI surveillance. During my preparation, I thought again through the issues of code-based algorithms (e.g. ICD-9) and I've come to the conclusion that they are useless for assessing the burden of HAIs and HAI trends and it's only going to get worse.

One area we (and many others) have looked at is the utility of ICD-9 code-based algorithms (ie administrative codes) for detecting HAIs efficiently. A key metric frequently reported by researchers is the sensitivity of a specific code or code algorithm, which is great if the purpose of the algorithm is to improve the efficiency of detection by manual methods. Thus, if the sensitivity is high-enough, you could use the code-based algorithm to reduce the number of charts that require an IP's review. If you are using codes in this way, great!  I have no problems with that.

However, many are now using code-based algorithms to track trends in specific HAIs and measure the burden of disease. My general feeling on these is that they should be completely avoided for several reasons:

1) No matter how sensitive the algorithm is, all we care about here (since we are not validating with manual review) is the positive predictive value (i.e. the proportion of all code-positive patients that actually have the HAI of interest)

2) The PPV is very low for almost all HAI algorithms

3) If we are doing our job and lowering the incidence of HAI per admission in our hospitals the PPV by definition will only get worse (given a fixed sensitivity and specificity)

To show you why I have these concerns I have constructed two 2x2 tables evaluating an excellent hypothetical code-based algorithm for UTI with a sensitivity and specificity set at 95%.  In this first 2x2, I have evaluated the performance of the algorithm when the HAI has a 5% incidence per admission (i.e., 5% of the admissions had a UTI). You can see that such a great algorithm with a high-prevalance of disease, has a poor PPV of 50% - like flipping a coin.

Now, assume we have done an amazing job and cut our HAI rate down to 1%.  Given the same hypothetical algorithm, our PPV is now a horrible 16%. Thus, as we get better at preventing HAIs, we get worse at detecting them using code-based algorithms. Are you comfortable saying UTIs are increasing or decreasing or are associated with a certain level of excess costs, when only 16% of the UTIs in your estimation are actual (true positive) UTIs?  Me neither.

Thursday, September 6, 2012

The High-Order Bit

The high-order bit of infection control, research, life:  "If you really look at the ones that ended up being successful..., often times it's the ones that are successful who loved what they did, so they could persevere when it got really tough. And the ones that didn't love it, quit. Because they're sane, right? Who would put up with this stuff if you don't love it? So it's a lot of hard work and it's a lot of worrying constantly. If you don't love it, you're going to fail." -Steve Jobs


Sunday, September 2, 2012

A tale of two outbreaks

Less than two weeks ago, we blogged about the KPC outbreak at the NIH Hospital. This outbreak garnered a lot of media attention, most of which was positive and highlighted how the epidemiologists at NIH worked to control the outbreak, as well as the relatively novel application of whole genome sequencing for outbreak investigation.

Today, the Daytona Beach News Journal reports on a local nosocomial outbreak of Acinetobacter infections. The article as well as the state health department report can be viewed here. Unfortunately, the hospital appears to have had problems with its infection prevention infrastructure that undoubtedly impacted its ability to control this difficult pathogen.

So what are the take home messages from these two outbreaks?
  1. The general public is highly interested in hospital infections and the mainstream media finds them to be quite juicy
  2. Transparency is paramount
  3. Infection Prevention Programs are enormously important patient safety programs that must be funded and staffed to maintain their effectiveness. 
Photo: Acinetobacter. Janice Carr, CDC.

Saturday, September 1, 2012

Legionella outbreak in Chicago

The Chicago Tribune is reporting that 10 cases of legionellosis have been linked to the JW Marriott in downtown Chicago during the time period July 16 through August 15. Three of the infected persons have died. The epidemiologic investigation has determined  that the epidemic strain has been found in a decorative fountain in the hotel lobby, as well as the swimming pool, whirlpool and locker rooms. Showerheads in guest rooms have not been found to be contaminated with the organism. The article also briefly mentions that "many" cases of Pontiac Fever, a less severe infection also caused by Legionella, are linked to the hotel.

Maybe we should just enjoy decorative water fountains outdoors. I'm aware of a recent case where infection prevention folks had to nix an architect's plan to construct an indoor water feature in a children's hospital despite reports of nosocomial legionellosis associated with these decorative fountains. Give us more sinks, not fountains!

Photo:  Legionella culture under ultraviolet light. CDC