Listeriosis in Pregnancy Max Brinsmead PhD FRANZCOG December 2010

Listeriosis Caused by Listeria monocytogenes Caused by Listeria monocytogenes A motile Gram-positive bacterium A motile Gram-positive bacterium Relatively ubiquitous in the environment Relatively ubiquitous in the environment Found in 1 – 15% of human faeces Found in 1 – 15% of human faeces Infection in animals is common Infection in animals is common Human infection is rare except: Human infection is rare except: When immunocompromised When immunocompromised Pregnant Pregnant Elderly Elderly Newborn Newborn In there were 3 cases per million population in the US In there were 3 cases per million population in the US But 30% of these were in pregnant women But 30% of these were in pregnant women

The Listeria Bacterium

Listeriosis Infection Begins with ingestion of contaminated food Begins with ingestion of contaminated food Will be phagocytosed by GI tract cells Will be phagocytosed by GI tract cells And thereafter continues a “hidden” life within cells And thereafter continues a “hidden” life within cells Spread by direct cell-to-cell transfer Spread by direct cell-to-cell transfer Not exposed to humoral antibodies Not exposed to humoral antibodies Controlled only by cell-mediated immunity Controlled only by cell-mediated immunity Which is reduced in pregnancy Which is reduced in pregnancy So pregnant women have a 20-fold increased susceptibility to this infection So pregnant women have a 20-fold increased susceptibility to this infection Risk is further enhanced by... Risk is further enhanced by... Splenectomy Splenectomy HIV infection HIV infection Steroids or immunosupressant drugs Steroids or immunosupressant drugs Diabetes Diabetes

Listeria Proliferation

Listeriosis in Pregnancy Fewer than 10 per 100,000 women Fewer than 10 per 100,000 women Infection may be asymptomatic Infection may be asymptomatic But the following symptoms also occur: But the following symptoms also occur: Fever (38.2 to C and mean of 38.9) Fever (38.2 to C and mean of 38.9) Malaise Malaise Flu-like symptoms such as headache and myalgia Flu-like symptoms such as headache and myalgia Rarely CNS infection with meningitis or abscess Rarely CNS infection with meningitis or abscess Transmission risk to the fetus about 50% Transmission risk to the fetus about 50% Untreated the risk of fetal death is 20 – 30% Untreated the risk of fetal death is 20 – 30% Pathognemonic finding is widespread abscesses & granulomas in the fetus (rare) Pathognemonic finding is widespread abscesses & granulomas in the fetus (rare)

Diagnosis Clinical diagnosis requires a high index of suspicion Clinical diagnosis requires a high index of suspicion Culture from blood, amniotic fluid or CSF is required Culture from blood, amniotic fluid or CSF is required Gram stain useful in only 33% of cases because the organism is intracellular and can resemble pneumococci, diptheroids and Haemophilus Gram stain useful in only 33% of cases because the organism is intracellular and can resemble pneumococci, diptheroids and Haemophilus WCC may be raised but often within the normal range for pregnancy WCC may be raised but often within the normal range for pregnancy

Treatment Use Ampicillin 2G every 6 – 8 hrs Use Ampicillin 2G every 6 – 8 hrs This high dose is recommended in order to cross to the amniotic fluid and membranes in sufficiently high concentrations This high dose is recommended in order to cross to the amniotic fluid and membranes in sufficiently high concentrations Gentamicin is said to be synergistic but not recommended in pregnancy (nephro oto toxic) Gentamicin is said to be synergistic but not recommended in pregnancy (nephro oto toxic) For penicillin allergy use Bactrim/Septrim For penicillin allergy use Bactrim/Septrim Sometimes Vancomycin Sometimes Vancomycin Maybe Erythromycin but placental passage is poor Maybe Erythromycin but placental passage is poor

Prevention Aims to reduce a pregnant woman’s exposure to possible contaminated food sources Aims to reduce a pregnant woman’s exposure to possible contaminated food sources Authorities recommend dietary advice to ALL pregnant women Authorities recommend dietary advice to ALL pregnant women But this has never been tested by RCT But this has never been tested by RCT Most cases are sporadic and the source is rarely identified Most cases are sporadic and the source is rarely identified Food sources have been identified either by outbreaks or microbiological examination Food sources have been identified either by outbreaks or microbiological examination

Typical Pregnancy Advice “ Listeria is a very rare infection that is mild in a mother but can be fatal to the baby in utero. You should NOT eat the following: Unpasteurised milk products esp. Soft cheeses, included feta, Brie, Camembert and ethnic-style cheeses. Unpasteurised milk products esp. Soft cheeses, included feta, Brie, Camembert and ethnic-style cheeses. (Hard cheeses, pasteurised, cottage & cheese spreads are okay) Raw seafood Raw seafood Uncooked meats and vegetables Uncooked meats and vegetables Cold-stored cooked meats and pates, Cold-stored cooked meats and pates, Milk products stored at >4 0 C Milk products stored at >4 0 C Beware of cross contamination from these sources Beware of cross contamination from these sources Wash all fruit and vegetables Wash all fruit and vegetables Cook foods at recommended temperatures” Cook foods at recommended temperatures”