CSF: Listeria monocytogenes  – Shipped May 2013


A simulated CSF sample collected from a 3 day old baby with sepsis was sent to category A laboratories.

Participants were expected to isolate, identify, and report Listeria monocytogenes. Laboratories were also expected to report the isolation of L. monocytogenes to Public Health Officials. No susceptibility was required for this challenge.

Correlation with results obtained for Gram smear, G131, was also expected.


  1. Identification of a Listeria species other than L. monocytogenes from a normally sterile site, particularly by means of biochemical testing, should be questioned and confirmed by an alternative method or referred to another laboratory for additional testing.
  2. Listeria monocytogenes is the only species within the genus that is not only a significant human pathogen, but also of Public Health importance. It is the third most common cause of bacterial meningitis in neonates in developed countries.

Full critique (PDF)

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