Listeriosis is an infectious illness caused by gram positive bacteria of the Listeriaceae family, genus Listeria, which comprises diverse species, of which only one causes illness in humans, the Listeria monocytogenes. Its name comes from the English surgeon Lord J. Lister. 

The relevant bacteria from the genus Listeria are regular, short gram-positive bacilli, neither spored nor branched, and may be seen in individual arrangement or forming short chains. In older cultivations they can appear forming filaments of 6-20 mm of length. They present from 1 to 5 flagella that confer mobility to 28ºC.

It is an important pathogen that causes infections in newborns, immunocompromised patients, the elderly, and expectant mothers (especially in the third trimester) and occasionally also in immunocompetent people. 

The clinical syndromes it can cause include febrile gastroenteritis, infection in pregnancy that appears as a flu-like syndrome, sepsis, CNS infections (meningitis, cerebritis or encephalitis) and can also cause focal syndromes like cutaneous or ocular infections, an oculoglandular syndrome (Parinaud syndrome), spinal or cerebral abscess and peritonitis. 

The diagnosis is established by culture and the treatment involves the administration of penicillin G or ampicillin and on occasion gentamicin (for more details on the dose, duration, etc consult the appropriate texts). Listeriosis during pregnancy usually has mild course for the mother, but can produce serious consequences in the foetus, as neonatal infection, premature birth and even death. During epidemics of listeriosis cultures of pregnant women who have been exposed should be obtained, although they may present with few symptoms or be asymptomatic. 

We present a case of perinatal death in a case of listeria infection in an expectant mother. In image 1 a view of the organs of the newborn abdominal cavity with multiple whitish round lesions in the liver and spleen is shown (arrows). This picture is known as granulomatose infantsepsis. 

And image 2, a granuloma is shown by HE staining.

In image 3, Gomori’s stain shows gram positive bacilli in a sample of liver tissue. 

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Authors:

Tomás Castiella Muruzábal
Juan Ignacio Pérez Calvo

Servicios de Anatomía Patológica y Medicina Interna
Hospital Clínico Universitario “Lozano Blesa”
Spain

Translation: Kelly Watt