Listeria monocytogenes with rocket tail

Listeria monocytogenes is a facultatively intracellular, gram-positive rod that grows over a broad temperature range, including refrigeration temperatures. This organism is motile during growth at low temperatures, demonstrating tumbling motility at low temperatures. At body temperature (37°C) it induces actin polymerization in host cell actin and forms “rocket tails” that facilitates intracellular movement and cell-to-cell spread across cell membranes, this way it avoids antibodies too....

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Mode of infection

Contaminated food ingestion (most common)

• Unpasteurized dairy products (cheese)

• Cold deli meats

In pregnancy

• Transplacental transmission

• Vaginal transmission during birth

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Clinical manifestation

• Meningitis and Septicemia are the most common presenting elements.
• Gastroenteritis- self-limiting illness in immunocompetent people. Nausea, vomiting, and diarrhea are presenting features.
• Bacteremia (septicemia) - L. monocytogenes septicemia presents with fever, chills, and myalgias/arthralgias. Meningeal symptoms, focal neurologic findings, or mental status changes may suggest the diagnosis.
• Meningitis- This diagnosis should be considered in all older or chronically ill adults with “aseptic” meningitis. The presentation is more frequently subacute (with illness developing over several days) nuchal rigidity and meningeal signs are less common.
• Meningoencephalitis and Focal CNS Infection- L. monocytogenes can directly invade the brain parenchyma, producing either cerebritis or focal abscess. The presentation may be biphasic, with a prodrome of fever and headache followed by neurologic decline and focal findings.
• Infection in Pregnant Women and Neonates- Listeriosis in pregnancy can cause miscarriage and stillbirth. The usual presentation is a nonspecific acute or subacute febrile illness with myalgias, arthralgias, backache, and headache.
• Granulomatosis infantiseptica is an overwhelming listerial fetal infection with miliary microabscesses and granulomas, most often in the skin, liver, and spleen.

Prevention

 Always eat cooked meat, wash fresh vegetables, carefully clean utensils, and avoid unpasteurized dairy products. The person at risk, like pregnant women and elderly people, should avoid soft cheeses and prevent or thoroughly reheat ready-to-eat and delicatessen foods.

Diagnosis

Symptoms of listerial infection are nonspecific and similar to other infectious diseases. Listeriosis occasionally affects healthy, young, nonpregnant individuals.

Illness should be considered in groups at risk -

• Pregnant women
• Elderly person
• Neonates
• Individuals immunocompromised by organ transplantation, cancer, or treatment with tumor necrosis factor antagonists or glucocorticoids

The diagnosis is typically made by culture of blood, cerebrospinal fluid (CSF), or amniotic fluid.

Treatment

Ampicillin is the drug of choice in most cases including infants and the elderly.

Revision for today https://creativemeddoses.com/topics-list/type-ii-hypersensitivity-antibody-mediated/