College of American Pathologists
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  First, tackle the basics


CAP Today




March 2009
Feature Story

Though the potential of molecular methods is great, Michael Pfaller, MD, professor emeritus of pathology at the University of Iowa College of Medicine, says laboratories can increase their diagnostic yield simply by doing the basics better. While updating a talk on laboratory diagnosis of Candida infections, Dr. Pfaller says, “I was struck by how little progress we have made as far as most labs are concerned in diagnosing and identifying fungal pathogens. You can talk ad nauseum about molecular approaches, but an ASM [American Society for Microbiology] survey found that fewer than five percent of labs in this country have any molecular mycology capability.” Dr. Pfaller attributes this largely to the lack of reliable commercial methods.

In his talk he chose to focus on more conventional techniques, such as blood culture systems, especially the different media these systems use and the evidence for their differential ability to detect Candida glabrata in the blood (Arendrup MC, et al. Clin Microbiol Infect. 2008;14:487–494). “There are also data to show that we could increase our yield by adding more specific fungal detection media,” Dr. Pfaller says (Meyer MH, et al. J Clin Microbiol. 2004;42:773–777). Each semiautomated system has an enriched blood culture medium with charcoal or resin that enhances growth of Candida, as well as fungal-specific media that inhibit growth of bacteria. In his talk, Dr. Pfaller suggested, “Consider using a fungal medium instead of an anaerobic medium as part of a ‘routine’ blood culture set.”

—William Check, PhD

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