2012/03/24 by Siren Rettedal, Iren H. Löhr, Olav Natås +3
paper · doi:10.1111/j.1600-0463.2012.02879.x
Neonatal intensive care units ( NICUs ) are vulnerable to nosocomial outbreaks caused by multiresistant E nterobacteriaceae, but no reports of NICU outbreaks of extended‐spectrum β‐lactamase ( ESBL ) producing K lebsiella pneumoniae have previously been published from countries with a low level of antimicrobial resistance such as the S candinavian countries. We describe a clonal outbreak of CTX ‐ M ‐15 ‐producing K lebsiella pneumoniae affecting 58 infants in the neonatal intensive care unit at S tavanger U niversity H ospital, N orway, during a period of 4 months, 2008–2009. The clone spread widely and rapidly in the NICU , and extensive interventions were required to terminate the outbreak. In contrast to previous outbreaks, only one infant acquired a systemic infection caused by the outbreak strain, probably due to a favourable epidemic strain lacking the most common virulence factors. A probable index case was identified, due to multiple positive breast milk samples collected from the infant's mother before and after the infant's transfer from another hospital. Breast milk samples from 3/18 (17%) mothers of colonized infants were positive for ESBL ‐producing K . pneumonia e. Vertical transmission of ESBL ‐producing bacteria has been shown previously,’but the possibility of transmission of ESBL ‐producing K . pneumoniae through expressed breast milk is reported here for the first time. The increasing occurrence of ESBL ‐producing’ E nterobacteriaceae should therefore encourage changes in diagnostic routines for bacterial screening of breast milk.