Blog | Thursday, August 3, 2017

Give me back my name

“There's a name for it,
names make all the difference in the world”
—Talking Heads

A little over two years ago, I told the sad story about how a contaminated blood culture became a central-line associated bloodstream infection (CLABSI). In that case, a “coryneform” or “diphtheroid” was more precisely identified by virtue of the adoption of mass spectrometry (MALDI-TOF) for organism identification.

As more labs adopt technologies that provide this greater precision for species identification, it becomes more important to understand how much of an impact this might have on central line-associated bloodstream infection (CLABSI) rates (it's not as if anything is riding on those rates, right?). So I was happy to see this small study in Infection Control & Hospital Epidemiology that begins to examine this issue. While this particular study is too small to help estimate the extent of the problem, it confirms that variation in species identification using different methods can impact a CLABSI designation. I hope this helps spur further evaluation not only of species identification methods, but of the broader issues around how laboratory advances impact health care-associated infection (HAI) definitions and rates.

What are the next steps for evaluating the impact of species identifications on CLABSI rates? First, the CDC's National Healthcare Safety Network (NHSN) needs to update their master organism lists to keep up with current laboratory capacity to identify organisms, and with changing nomenclature. I know they are doing this, because I've been involved in that ongoing effort. Second, we should be able to use NHSN data to drill down on this problem, but can only do so if we know which lab methods are being used in each hospital for organism identification. So NHSN has now added questions to their annual survey to elicit this information. My hope is that we can use that information to compare CLABSIs among those organism groups most likely to affected by more precise species identification methods (e.g., gram-positive rods).

As long as HAI definitions hinge on laboratory results, HAI rates will be very sensitive to technological advances (as well as to lab ordering practices). This dynamic receives far too little attention.

Daniel J. Diekema, MD, FACP, practices infectious diseases, clinical microbiology, and hospital epidemiology in Iowa City, Iowa, splitting time between seeing patients with infectious diseases, diagnosing infections in the microbiology laboratory, and trying to prevent infections in the hospital. This post originally appeared at the blog Controversies in Hospital Infection Prevention.