Staphylococcus argenteus and Staphylococcus schweitzeri are two recently described bacterial species related to Staphylococcus aureus. In this "Test in Focus" episode of the "Answers From the Lab" podcast, Audrey Schuetz, M.D., discusses Mayo Clinic Laboratories' unique PCR assay that identifies these Staphylococcus species.

"Our assay can differentiate Staphylococcus argenteus and Staphylococcus schweitzeri from Staphylococcus aureus. That is unique," Dr. Schuetz says. "Other available methods, even some of the very advanced methods, don't differentiate these species."

Mayo Clinic Laboratories’ assay can clarify whether bacterial colonies contain the recently described Staphylococcus species. "We do not run the assay on direct patient specimens, such as nasal swabs. It's intended for use on isolates when we have an unclear identification of Staphylococcus species," Dr. Schuetz says. "The organism may look like a staph species, but the color might not be quite right. Mass spectrometry, which many of us rely on in the laboratory, might be delivering an unclear reading."

Precise identification and reporting of Staphylococcus species benefit patient care. Clinicians might not be familiar with the newly described species, which — with Staphylococcus aureus — comprise the "Staphylococcus aureus complex."

"Clinicians who don't recognize these newly described organisms might think of them as coagulase-negative staphylococci — which generally aren't as concerning clinically as Staphylococcus aureus," Dr. Schuetz says. "The lab results might not be taken as seriously. Clinicians could end up providing inappropriate or suboptimal treatment."

Listen to learn more about how the IDENT assay can provide more informative results for Staphylococcus testing.

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Testing

IDENT  | Organism Referred for Identification, Aerobic Bacteria

Useful information

• Identification of pure isolates of aerobic bacteria
• Differentiation of members of the Staphylococcus aureus complex (S aureus, S argenteus, S schweitzeri)

Specimen requirements

• Supplies: Infectious Container, Large (T146)
• Specimen Type: Pure culture of organism from source cultured
• Container/Tube: Agar slant or other appropriate media
• Specimen Volume: Entire specimen
• Collection Instructions:
  • Perform isolation of infecting bacteria.
  • Bacterial organism must be submitted in pure culture, actively growing. Do not submit mixed cultures.

Performance information

• Analytic time: 5 to 10 days
• Day(s) and time(s) performed: Monday and Friday

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