Recent recalls of products because of potential Listeria contamination have led to numerous requests of the WSLH for Listeria culture testing.
The WSLH does not routinely perform primary culture of clinical specimens for Listeria without Wisconsin Division of Public Health (WDPH) approval.
Diagnosis of listeriosis is confirmed only after isolation of Listeria monocytogenes from a normally sterile site, such as blood, spinal fluid (in the setting of nervous system involvement) or amniotic fluid/placenta (in the setting of pregnancy).
According to the CDC, stool samples are of limited use and are not recommended (http://www.cdc.gov/listeria/diagnosis.html).
The CDC has also provided a suggested framework for medical management of persons at elevated risk for invasive listeriosis who were exposed to Listeria monocytogenes.
If a clinician or local health department has additional questions about testing for Listeria or suspects a patient has listeriosis they can contact an epidemiologist at the Wisconsin Division of Public Health (608-267-9003).
The WSLH continues to request submission of ALL Listeria monocytogenes isolates from sterile body sites for surveillance purposes.