Good Intentions Does not Always Mean Good Policy

How often do negative studies influence our behavior, or better yet our policies? For those of you that are familiar with the work I have published, you know that I published a lot of material focused on MRSA; emerging resistance, community-emergence, burden of disease, attributable cost, risk factors, and on.  I was in a position at CDC to access and synthesize a lot of data, with a goal of putting the problem in perspective and ideally affect policy. Well intended as it was, I remember very clearly in mid-2007 when policy got way ahead of the science. Two independent (but related) events occurred on October 16-17, 2007 that led to several years of a watershed of policy developments. Although I give a huge amount of credit to the very passionate and important patient advocates and consumers that built momentum for the policies – but with hindsight the policy inertia was really overcome when a senior student at Staunton River High School died on October 16 from MRSA sepsis—MRSA he acquired in the community. The press linked that death to Dr. Elizabeth Bancroft’s editorial that same week stating “…more people die of MRSA in the U.S. than of AIDS” published on October 17. Many of us see much of the public reporting and mandatory reporting policies have opened up real pathways for additional hospital resources to invest in HAI prevention. However all of us should recognize some policies of that era are likely in place that really should be re-examined. 

One of these is the Illinois 210 ILCS 83/ legislation requiring all patients admitted to intensive care units be screened for MRSA by nasal active surveillance testing (AST). Lin and colleges just published a negative study with a lot of important findings. To many, the findings will not be a surprise (CID May 15 2018, pp 1535-1539)

• Lin worked with 51 intensive care units at 25 hospitals over 5 years starting within months of enactment of this mandate to evaluate any changes in ICU MRSA prevalence through periodic point prevalence surveys performed by trained study staff during the time of this mandate. The study was a quasi-experimental time series evaluation but without a real before observation group and no control group. However, I believe that any impact would have been additive over time – the first year would have been a sort of wash in period for an intervention as broad in participation as this.  They sampled 3909 patients having the power to even detect an absolute difference in carriage as small as a 1.9% change in prevalence (eg, 10% vs 8.1%) – but they detected none. No change in prevalence of MRSA on these patients. 
  

• Compliance was high overall (93%), admission prevalence was comparable to other studies (9.7%), and overall, at any given survey of known positive patients and unknown, 11.1% were positive in any given month, in any given year of this study.  Sure, time to placement of contact precautions lagged from test turnaround time or from time to test result to actual placement of precautions, but most notably the mandated testing was only 84% sensitive compared to best testing methods  employed by the study investigators. This is the real world after all.

• While these ICUs have invested time, effort, and money into these admission swabbing and targeted placement of contact precautions, the prevalence of MRSA carriage has not budged in these intensive care unit patients.

There may be many reasons the hospitals in Illinois overall are seeing an estimated 30% decrease in their hospital-onset MRSA BSI (as most states are) since the 2010 NHSN baseline, but admission screening isn’t one of them. Maybe its CLABSI prevention, or that uptake of the percentage of study patients receiving CHG baths. However, this study suggests it was not the mandated AST for all ICU patients admitted to the ICU. These patients are bringing their MRSA in with them, let’s free up staff time to prevent the infections.

I know there are many major federal policies we all can be passionate about changing or starting, these are crazy days. But when the scientific evidence is so strong illustrating that a very well-intended policy regarding use of nursing and infection control resources does not have the intended impact – change it. Nursing care can better be spent caring for patients, practicing best infection control for all patients in these intensive care units. 

Ebola Screening: Hey CDC! Is it an AND or an OR?

Like many of you, we've all been assisting with Ebola planning for the past several months. Just today, Mike and I were in another planning meeting and the subject of our screening algorithm came up. Mike had noticed that the September 4th CDC Definition of Person Under Investigation (PUI) that we've been using: "fever of greater than 38.6 degrees Celsius or 101.5 degrees Fahrenheit, AND additional symptoms such as severe headache, muscle pain, vomiting, diarrhea, abdominal pain, or unexplained hemorrhage" is now different in the PDF algorithm that the CDC posted on October 2nd. It now says "FEVER OR EVD symptoms." I've included the relevant portion of the PDF algorithm above.

This may seem like a minor change, but for many facilities it will be a big deal. To go from a relatively sensitive "fever AND" to a very sensitive "fever OR" is not a small change. This may require EDs and clinics to screen additional patients and result in a large increase in laboratory tests being sent for Ebola diagnosis. I think that CDC meant to suggest that fever is enough to prompt a travel history, but now anyone with fever, headache, weakness, muscle pain, vomiting, diarrhea, abdominal pain or hemorrhage will also need to be asked a travel history. In practice this will mean that every patient that walks into an ED or clinic should be asked a travel history first and then asked about symptoms. I'm not convinced this should happen and feel much more comfortable with having symptoms guide travel history. But since almost any general complaint is now included, we may be left with no other choice but to ask travel history first. And of course, we don't know what CDC wants us to do since both documents are live and offer conflicting advice.

So, which is it CDC?  Is it an AND or an OR?

Extranasal MRSA Colonization

Medical decision makers LOVE a good systematic review.  This is especially true if that review synthesizes the literature surrounding a key parameter input for their decision models. Sometimes these studies can even have clinical importance beyond informing decision-analytic models, which is the case here.

In the February 2013 ICHE, James McKinnell and colleagues completed a systematic review that estimated the incremental benefits of testing for MRSA colonization at extra-nasal sites. They combed 4,381 abstracts and 735 articles to find 23 high-quality studies comparing any-site (extranasal+nasal) screening to nasal screening for MRSA. The specifics are outlined in Table 2 below, while the overall message is that an additional one-third of patients will be detected if extranasal sites are screened. What this means as far as changing practice and the cost-effectiveness of adding extranasal sites to screening algorithms will have to wait for those future pesky decision-analytic models. Stay tuned!

Reference: Quantifying the Impact of Extranasal Testing of Body Sites for Methicillin-Resistant Staphylococcus Aureus Colonization at the Time of Hospital or Intensive Care Unit Admission James A. McKinnell, MD; Susan S. Huang, MD, MPH; Samantha J. Eells, MPH; Eric Cui, BS; Loren G. Miller, MD, MPH Infection Control and Hospital Epidemiology , Vol. 34, No. 2 (February 2013), pp. 161-170

Papers you should read, September 2011

We know. Postings have been light these past few weeks. Hey, we are getting ready for ICAAC and IDSA. So cut us some slack, already...(joking)

OK, in a matter of full disclosure, I have conflicts of interest with both of these papers, so following our standard practice of not critiquing papers where we have conflicts, I will leave the interpretation of each paper to you, our dear readers.

Click to enlarge: Frequency of non-prescription use of antimicrobials in the general population

Dan Morgan, who was our invited contributor on Veterans Day, has published a review of world-wide, non-prescription antimicrobial use in this months Lancet ID.  The review included 117 articles including 35 community surveys published between 1970 and 2009. I've pasted a summary figure above.

Co-blogger Dan has a paper coming out in ICHE (ahead of print) surveying IDSA's EIN Network of ID clinicians on their pre-op screening and decolonization practices for S. aureus. The survey included 488 respondents, who had knowledge of their hospital's pre-op screening. Overall, 60% screened for S. aureus with 47% screening for MRSA only and 13% for all S. aureus. Less than 20% screened extranasally. Screening method was led by PCR (36%) followed by standard culture (30%) and chromogenic agar (27%). Additionally, 52% decolonized with 31% decolonizing MRSA carriers, 8% decolonizing S. aureus carriers and 15% decolonized irrespective of colonization status. To find out more, you need to read the paper!

Nosing around for staphylococci

In my last post about the newly described MRSA strains that carry the mecA_LGA251, I referred again to the “empty cassette variants” (or “mecA dropouts”) that are missed by commercial MRSA PCR tests that target the orfX gene but don’t contain mecA primers. I also mentioned that we’d soon be publishing our first year of experience with this. Well, here is the short report I was talking about, describing our ~8% rate of false positivity due to empty cassette variants, and characterizing the strains in question. We found substantial genetic diversity among the “drop-out” strains, meaning that the problem wasn’t due to the introduction of a single clone. When we tested these MSSA isolates using the newer GeneXpert MRSA/SA Nasal Assay (the “Nasal Complete” assay), they were correctly identified as S. aureus but not MRSA (this new assay has primers for the mecA gene). Even the “Nasal Complete” assay is susceptible to false positives, though, from the simultaneous presence of an MSSA and a methicillin-resistant coagulase-negative staphylococcus (MR-CoNS) in the same nose (the prevalence of MR-CoNS + MSSA co-colonization was 3.4% in one study). Indeed, the package insert describes a PPV of about 75% for the Nasal Complete—for MRSA, the 25% “false positives” divide equally between those for which culture was negative (which might reflect increased sensitivity of PCR) and those for which the culture grew only MSSA (which may reflect MR-CoNS/MSSA co-colonization). Who knew the nares would be such a vexing place for those who design and market PCR tests?

Ctrl+F

…will bring up the “Find and Replace” tool in Microsoft Word. Illinois legislators, you may want to use this tool today, so you can get yourselves a shiny new law to deal with the latest emerging antimicrobial resistance threat.

Hint: you’ll want to find “MRSA”, and replace with “KPC”. Make sure to go to “search options” and click on “Match Case”, or you’ll mess it all up.

That should do it.

Links:
Illinois screening legislation
IDSA abstract on emergence of KPC-producers in Illinois
Chicago Tribune story

Sensitivity of perianal swabs for MDR-GNR

Quick last abstract from ICAAC.  Graham Snyder et al. from Beth Israel Deaconess Medical Center in Boston enrolled 35 patients with known multidrug-resistant Gram-negative bacteria in clinical cultures (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterobacter cloacae, Proteus mirabilis, and Morganella morganii). Each patient received a perianal swab. The sensitivity was 79%. It was a small study with the usual caveats.

Conflict of Interest: Graham was a medical resident that I worked and published with at Maryland.

link to medpage article