title: The first occurrence of a CTX-M ESBL-producing Escherichia coli outbreak mediated by mother to neonate transmission in an Irish neonatal intensive care unit.
abstract: Escherichia coli (E. coli) comprise part of the normal vaginal microflora. Transfer from mother to neonate can occur during delivery resulting, sometimes, in neonatal bacterial disease. Here, we aim to report the first outbreak of CTX-M ESBL-producing E. coli with evidence of mother-to-neonate transmission in an Irish neonatal intensive care unit (NICU) followed by patient-to-patient transmission.
  
  
  
  Investigation including molecular typing was conducted. Infection was defined by clinical and laboratory criteria and requirement for antimicrobial therapy with or without positive blood cultures. Colonisation was determined by isolation without relevant symptoms or indicators of infection.
  
  
  
  Index case was an 8-day-old baby born at 34 weeks gestation who developed ESBL-producing E. coli infections at multiple body sites. Screening confirmed their mother as colonised with ESBL-producing E. coli. Five other neonates, in the NICU simultaneously with the index case, also tested positive. Of these, four were colonised while one neonate developed sepsis, requiring antimicrobial therapy. The second infected neonate's mother was also colonised by ESBL-producing E. coli. Isolates from all eight positive patients (6 neonates, 2 mothers) were compared using pulsed-field gel electrophoresis (PFGE). Two distinct ESBL-producing strains were implicated, with evidence of transmission between mothers and neonates for both strains. All isolates were confirmed as CTX-M ESBL-producers. There were no deaths associated with the outbreak.
  
  
  
  Resources were directed towards control interventions focused on hand hygiene and antimicrobial stewardship, which ultimately proved successful. Since this incident, all neonates admitted to the NICU have been screened for ESBL-producers and expectant mothers are screened at their first antenatal appointment. To date, there have been no further outbreaks.
authors.affiliation: Department of Clinical Microbiology, University Hospital Limerick, Limerick, Ireland.|Centre for Interventions in Infection, Inflammation and Immunity (4i), Graduate Entry Medical School, University of Limerick, Limerick, Ireland.
authors.forename: Ciara
authors.initials: C
authors.lastname: O'Connor
authors.affiliation: Department of Paediatrics, University Maternity Hospital Limerick, Limerick, Ireland.
authors.forename: Roy K
authors.initials: RK
authors.lastname: Philip
authors.affiliation: Department of Paediatrics, University Maternity Hospital Limerick, Limerick, Ireland.
authors.forename: John
authors.initials: J
authors.lastname: Kelleher
authors.affiliation: Department of Clinical Microbiology, University Hospital Limerick, Limerick, Ireland.
authors.forename: James
authors.initials: J
authors.lastname: Powell
authors.affiliation: Infection Prevention and Control Team, University Hospital Limerick, Limerick, Ireland.
authors.forename: Alan
authors.initials: A
authors.lastname: O'Gorman
authors.affiliation: Infection Prevention and Control Team, University Hospital Limerick, Limerick, Ireland.
authors.forename: Barbara
authors.initials: B
authors.lastname: Slevin
authors.affiliation: Antimicrobial Resistance and Healthcare Associated Infections (AMRHAI) Reference Unit, Public Health England, London, UK.
authors.forename: Neil
authors.initials: N
authors.lastname: Woodford
authors.affiliation: Antimicrobial Resistance and Healthcare Associated Infections (AMRHAI) Reference Unit, Public Health England, London, UK.
authors.forename: Jane F
authors.initials: JF
authors.lastname: Turton
authors.affiliation: Antimicrobial Resistance and Microbial Ecology Group, School of Medicine, National University of Ireland, Galway, Ireland.
authors.forename: Elaine
authors.initials: E
authors.lastname: McGrath
authors.affiliation: Department of Clinical Microbiology, University Hospital Limerick, Limerick, Ireland.
authors.forename: Cathriona
authors.initials: C
authors.lastname: Finnegan
authors.affiliation: Department of Clinical Microbiology, University Hospital Limerick, Limerick, Ireland.
authors.forename: Lorraine
authors.initials: L
authors.lastname: Power
authors.affiliation: Department of Clinical Microbiology, University Hospital Limerick, Limerick, Ireland.|Centre for Interventions in Infection, Inflammation and Immunity (4i), Graduate Entry Medical School, University of Limerick, Limerick, Ireland.
authors.forename: Nuala H
authors.initials: NH
authors.lastname: O'Connell
authors.affiliation: Centre for Interventions in Infection, Inflammation and Immunity (4i), Graduate Entry Medical School, University of Limerick, Limerick, Ireland. colum.dunne@ul.ie.
authors.forename: Colum P
authors.initials: CP
authors.lastname: Dunne
mesh_terms: D000328:Adult; D004196:Disease Outbreaks; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics* / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000151:congenital / Q000175:diagnosis* / Q000382:microbiology / Q000635:transmission; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D017053:Infection Control; D018445:Infectious Disease Transmission, Vertical; D007363:Intensive Care Units, Neonatal; D007494:Ireland; D008297:Male; D058889:Molecular Typing; D009035:Mothers; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000382:microbiology; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism
chemical_list: D029968:Escherichia coli Proteins; D001618:beta-Lactamases; C000602253:beta-lactamase CTX-M, E coli
keywords: CTX-M; ESBL; Escherichia coli; Ireland; NICU; Outbreak