Listeria

Listeria monocytogenes is a Gram positive bacillus which has the unusual ability to multiply at low temperatures. It is typically spread via contaminated food, typically unpasteurised dairy products. Infection is particularly dangerous to the unborn child where it can lead to miscarriage.

Features - can present in a variety of ways

• diarrhoea, flu-like illness
• pneumonia , meningoencephalitis
• ataxia and seizures

Suspected Listeria infection should be investigated by taking blood cultures. CSF may reveal a pleocytosis, with 'tumbling motility' on wet mounts

Management

• Listeria is sensitive to amoxicillin/ampicillin (cephalosporins usually inadequate)
• Listeria meningitis should be treated with IV amoxicillin/ampicillin and gentamicin

In pregnant women

• pregnant women are almost 20 times more likely to develop listeriosis compared with the rest of the population due to changes in the immune system
• fetal/neonatal infection can occur both transplacentally and vertically during child birth
• complications include miscarriage, premature labour, stillbirth and chorioamnionitis
• diagnosis can only be made from blood cultures
• treatment is with amoxicillin