Fetal Loss and Preterm Birth Caused by Intraamniotic Haemophilus influenzae Infection, New Zealand

Abstract

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Genome Characterisation of Invasive Haemophilus influenzae in Pregnancy: The Noticeable Placental Tissue Tropism Is Distributed across the Species Rather Than Linked with Capsulation or Particular Clones

“…Maternal invasive H. influenzae infection during the first 24 weeks of pregnancy is associated with a high rate of foetal loss, while stillbirth is rare in the second half of pregnancy. Only a single neonatal bacteraemia case is included, but our case #8 supports the recognition of early-onset septicaemia with a substantially increased risk among preterm neonates, where maternal bacteraemia is rarely documented, and with a grave outcome [7,8,10].…”

“…A study from Scotland in 2017-2018 reviewed all post-mortems at <24 weeks gestation with histologically proven acute chorioamnionitis on placental histology; H. influenzae accounted for 20% of infections associated with early pregnancy loss prior to week 24 [28]. The inconsistent definition, or reporting, of invasive H. influenza infections in pregnancy is apparent from the contrasting numbers of bacteraemia, from 100% in the US ABC catchment areas 2008-2019 [7] to 34% in the New Zealand study [8].…”

“…An essential clinical question relates to the port of entry of the pathogen. One possible hypothesis is that sexually acquired vagino-cervical H. influenzae infection is the proximate cause of invasive infections in pregnant women [8]. There are some uncertainties about this hypothesis.…”

“…influenzae diseases associated with pregnancy encompass maternal bacteraemia in pregnancy and postpartum, chorioamnionitis, and neonatal infection. A distinct epidemiology was reported from New Zealand, consisting of 52 maternal and/or neonatal invasive H. influenzae infections during 2008-2018 [8]. While infant bacteraemia was detected in 15 of 16 neonatal infections, bacteraemia was only documented in 13 of 38 maternal infections, where the predominant culture-positive specimen was placental tissue or products of conception.…”

“…Neonatal invasive H. influenzae infections are almost exclusively bacteraemia cases with isolation of the pathogen within 24 h of birth. Maternal bacteraemia is not the principal, documented source of neonatal infection, as it is only observed in 6-15% of cases [7,8,10].…”