Outbreak of OXA-48-producing Enterobacteriaceae in a neonatal intensive care unit in Western Sweden

AbstractIn 2015, an outbreak caused by OXA-48-producingEnterobacteriaceae affected a neonatal intensive care unit at a Swedish University Hospital. The aim was to explore the transmission of OXA-48-producing strains between infants and the transfer of resistance plasmids between strains during the outbreak. Twenty-four outbreak isolates from ten suspected cases were whole-genome sequenced. A complete assembly was created for the index isolate (Enterobacter cloacae) and used as a mapping reference to detect its plasmids in the remaining isolates (17Klebsiella pneumoniae, 4Klebsiella aerogenes, and 2Escherichia coli). Strain typing was performed using core genome MLST and SNP analysis. As judged from sequencing and clinical epidemiological data, the outbreak involved nine cases (two developed sepsis) and four OXA-48-producing strains:E. cloacae ST1584 (index case),K. pneumoniae ST25 (eight cases),K. aerogenes ST93 (two cases), andE. coli ST453 (2 cases). Two plasmids from the index strain, pEclA2 and pEclA4, carryingblaOXA48 andblaCMY-4, respectively, were traced to allK. pneumoniae ST25 isolates.Klebsiella aerogenes ST93 andE. coli ST453 harboured either only pEclA2, or both pEclA2 and pEclA4. One suspected case harbouring OXA-162-producingK. pneumoniae ST37 could be excluded from the outbreak. Once initiated by anE. cloacae strain, the outbreak was caused by the dissemination of aK. pneumoniae ST25 strain and involved inter-species horizontal transfer of two resistance plasmi...
Source: European Journal of Clinical Microbiology and Infectious Diseases - Category: Microbiology Source Type: research