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For further information, see CMDT Part 33-08: Listeriosis
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Essentials of Diagnosis
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Ingestion of contaminated food product
Undifferentiated fever in a pregnant woman in her third trimester
Altered mental status and fever in an elderly or immunocompromised patient
Obtain blood and cerebral spinal fluid cultures to confirm diagnosis
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General Considerations
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Listeria monocytogenes is a facultative, motile, gram-positive rod that is capable of invading several cell types and causes intracellular infection
Most cases of infection are sporadic, but outbreaks have been traced to eating contaminated food, including
Outbreaks have been associated with significant morbidity and mortality in infected persons
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Five types of infection are recognized
Infection during pregnancy
Usually in the last trimester
Produces a mild febrile illness without an apparent primary focus and may resolve without therapy
However, approximately 1 in 5 pregnancies complicated by listeriosis result in spontaneous abortion or stillbirth and surviving infants are at risk for clinical neonatal listeriosis
Granulomatosis infantisepticum
Bacteremia with or without sepsis syndrome
Meningitis
Affects infants younger than 2 mo and adults, ranking third among the common causes of bacterial meningitis
Adults with meningitis are usually immunocompromised
Cases have been associated with HIV infection
Focal infections occur rarely and include
Adenitis
Brain abscess
Endocarditis
Osteomyelitis
Arthritis
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Positive blood or cerebrospinal fluid culture
In meningitis, cerebrospinal fluid shows a neutrophilic pleocytosis
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Tables 30–4 and 30–2
Drug of choice is ampicillin, 8–12 g/day intravenously in four to six divided doses (the higher dose is recommended in cases of meningitis) for 14–21 days
Gentamicin at 5 mg/kg/day once or in divided doses intravenously is synergistic with ampicillin; combination therapy may be considered during the first few days of treatment to enhance eradication of organisms
Trimethoprim-sulfamethoxazole
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