Listeria Flashcards
What is the incidence of Listeria in pregnancy?
1:10 000 pregnancies
What foods are at risk of carrying listeria?
• raw/uncooked/smoked meat and seafood, ready to eat chilled seafood;
• deli meats, cooked cold meat, pate, meat spreads;
• leftovers (more than 24 hours after cooking);
• pre-prepared salads, smorgasbords, buffets;
• unpasteurised milk and soft-serve ice cream;
• soft cheeses (brie, camembert, ricotta, feta, blue);
• unwashed raw fruit and vegetables; and
• raw eggs or foods containing raw or partially cooked eggs.
Hard cheeses, such as cheddar, are safe. Processed cheese, plain cream cheese and plain cottage cheese are fine if purchased sealed and stored in the fridge.
How to reduce the risk of catching listeria
Freshly prepared and cooked foods have low levels of bacteria. Bacteria grow over time, so avoid eating food if it has been made more than 24 hours since being prepared. Always reheat to steaming hot.
• Raw fruit and vegetables should be washed thoroughly before eating.
• Listeria is destroyed in normal cooking, so freshly cooked hot food is safe if eaten straight away
• Even at-risk foods risk can be eaten safely if heated above 74 degrees Celsius for over two minutes.
Wash hands before preparing foods
• Thoroughly cook raw food from
animal sources
• Keep uncooked meat separate from .vegetables, cooked foods and ready-to-eat foods
• Eat freshly cooked foods.
• Avoid eating dips and salads in which
raw vegetables may have previously
been dipped
• and salads in which raw vegetables
may have previously been dipped
• Use separate cutting boards for raw
meats and foods that are ready to
eat e.g. cooked foods and salads
• Avoid foods at risk of listeria
What is listeria
Listeria is a Gram positive bacillus
Incubation
incubation is 11-70 days
Clinical presentation
Flu like illness, fever, malaise, 1/3 are asymptomatic
Investigations for listeria
blood, vaginal and cervical cultures, placental culture post partum
Prognosis
Maternal and fetal risks
Maternal - Septicaemia, meningitis, encephalitis
Fetal - Early pregnancy infection can result in miscarriage Fetal infection can cause brown liquor (can be confused with meconium) PTL
In women with listeriosis, risk of fetal death was up to 19%
54% early infection - this is from transplacental spread and results in congenital pneumonia
23% infection after 2 days - tends to present with meningitis
Overall fetal mortality 50%
Treatment
Amoxicillin for 10-14 days
What are suspicious neonatal signs for listeria
• placental, cord or post-pharyngeal granulomas (“granulomatosis infantiseptica”) • Multiple small skin granuloma, papular or pustular skin rash (“granulomatosis infantiseptica”) • Meconium stained/discoloured liquor < 34 weeks gestation • Pneumonitis • Purulent conjunctivitis
What are the considerations for adding gent to treatment regime?
Synergism for penicillin or ampicillin with gentamicin has only been reported in-vitro. The risk for ototoxicity and fetal toxicity needs to be balanced
with clinical risk.
**Gentamicin is thus is generally recommended in combination with ampicilllin/amoxycillin in severe infections, including meningitis.
Dosing is not standardised and should be in accordance with local guidelines. Dosing ranges cited include “maximum of 2.5 mg/kg/day”1 to “maximum
of 360 mg per day, as an infusion
What is the rate of normal carriage of transient colonisation of listeria?
Faecal carriage of L. monocytogenes is found in 0.6-16% of the population. Transient colonisation of the GI tract is common but invasive disease is rare.
The significance of maternal faecal excretion of listeria in perinatal infection is uncertain.
What is included in the septic work up of an unwell neonate
Septic workup • Culture placenta • Culture: Superficial swabs, blood cultures, urine & CSF with Gram stain • CXR • FBE/diff
Surface cultures with Gram stain from placenta, meconium, rectal and external ear canal have all been found to have a high yield in
isolating the organism
are any other antibiotics able to be used?
triprim
not in T1
For penicillin allergic or lact of response to treatment
Listeria is resistant to Cephalosporins
what are the fetal / neonatal presentations of listeria?
mortality rates
Preterm delivery is common.
Mortality rates range from 3-60% in infected neonates born alive.
• Perinatal listeria can present as early-onset disease (within 7 days of birth, mean 1.5 days) often associated with prematurity and fulminant disease. Mortality is high (20–60%).
• Late onset disease occurs typically in term infants (7 days to 6 weeks, mean onset ~14 days), often presenting with meningitis, but can
be more non-specific sepsis (fever, irritability, anorexia, diarrhoea, lethargy). Mortality is 10–20%.
