Mother to Child Transmission of Extended Spectrum β-Lactamase Producing Enterobacteriaceae

BACKGROUND Preterm infants are at high risk for extended spectrum beta-lactamase producing Enterobacteriaceae (ESBL-E) sepsis and neonatal intensive care unit (NICU) outbreaks. Maternal colonization with ESBL-E may be precursory to maternal-neonatal transmission. However, there is no consensus regarding surveillance of pregnant women for ESBL-E colonization. AIM To identify pairs of mothers and offspring harbouring same-strain ESBL-E colonization and to determine whether maternal transmission may play a role in increasing ESBL-E carriage in preterm infants. METHODS A one-year analysis from an ongoing, prospective ESBL-E surveillance of mothers of premature infants and their offspring. Mother-infant pairs colonized with the same bacteria underwent strain analysis using pulse-field gel electrophoresis (PFGE). Clinical parameters were collected from the hospital computerized records. FINDINGS Between January 2015 - January 2016, 313/409 (76.5%) mothers and all 478 (100%) infants were screened for ESBL-E colonization; carriage rates were 21.5% and 14.8%, respectively. Four (5.6%) carrier infants developed late onset sepsis and 2 (2.8%) died. Twenty-five mother-infant pairs colonized with the same bacterial strain were identified; a subgroup of 10 pairs of isolates underwent PFGE, and 70% displayed identical PFGE fingerprint. No similarities were found between isolates recovered from unrelated neonates and mothers. A significant earlier ESBL-E colonization was found in infants of mothers colonized at birth (P <0.001) compared with infants of non-colonized mothers. CONCLUSIONS ESBL-E carriage rates in mothers and NICUs infants with a non-negligible maternal-neonatal ESBL-E transmission, in our region indicates that maternal colonization surveillance, and/or further infection control interventions should be considered.