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Listeria monocytogenes Infection (cont.)

What is the diagnosis for listeriosis?

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.

What is the treatment for listeriosis?

Treatment for listeriosis includes intravenous antibiotics, as well as supportive care. The prompt initiation of antibiotics when the diagnosis is suspected or confirmed can hasten recovery and prevent the more serious potential complications sometimes encountered with listeriosis.

  • Antibiotics
    • Ampicillin (Principen) is generally considered the antibiotic of choice, though there are other acceptable antibiotic choices.
    • Involve an infectious disease specialist to assist with appropriate antibiotic selection and duration of treatment.
    • The duration of treatment with antibiotics varies with the severity of illness and the particular areas involved with disseminated infection.
  • Supportive care
    • Intravenous fluids to prevent dehydration or to maintain an adequate blood pressure may be necessary.
    • Intravenous medications for nausea and/or vomiting may be administered.
    • Patients with low blood pressure may require intravenous medications to increase their blood pressure (pressors).
    • Patients with severe listeriosis may require mechanical ventilation (breathing machine) for respiratory support.

Most authorities believe that individuals, even those at high-risk, who ingest food products contaminated with Listeria monocytogenes do not require treatment if they do not have any signs or symptoms of infection. However, careful consideration must be taken in the pregnant patient, as listeriosis can be potentially devastating to the fetus and newborn.

Medically Reviewed by a Doctor on 11/20/2017
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