Listeria monocytogenes Infection (cont.)
IN THIS ARTICLE
Diagnosing listeriosis promptly can be challenging, as it can initially present clinically similar to many other gastrointestinal infections. The patient's history can be critical, as it may provide information about exposure to certain food products known to harbor Listeria monocytogenes. Making a clinical diagnosis can be facilitated if there is a known outbreak of listeriosis.
The definitive diagnosis of infection with Listeria monocytogenes is confirmed by culturing and isolating the organism from blood, cerebrospinal fluid, amniotic fluid, or the placenta on specialized laboratory media. Isolating the specimen from stool samples is unreliable, as is serologic testing. Imaging studies, such as a CT scan or MRI of the brain, may be ordered to detect a brain abscess, for example. A spinal tap (lumbar puncture) to obtain cerebrospinal fluid may also be performed if there is suspicion of central nervous system infection.