title: MRSA transmission on a neonatal intensive care unit: epidemiological and genome-based phylogenetic analyses.
abstract: BACKGROUND
  Methicillin-resistant Staphylococcus aureus (MRSA) may cause prolonged outbreaks of infections in neonatal intensive care units (NICUs). While the specific factors favouring MRSA spread on neonatal wards are not well understood, colonized infants, their relatives, or health-care workers may all be sources for MRSA transmission. Whole-genome sequencing may provide a new tool for elucidating transmission pathways of MRSA at a local scale.
  
  
  RESULTS
  We applied whole-genome sequencing to trace MRSA spread in a NICU and performed a case-control study to identify risk factors for MRSA transmission. MRSA genomes had accumulated sequence variation sufficiently fast to reflect epidemiological linkage among individual patients, between infants and their mothers, and between infants and staff members, such that the relevance of individual nurses' nasal MRSA colonization for prolonged transmission could be evaluated. In addition to confirming previously reported risk factors, we identified an increased risk of transmission from infants with as yet unknown MRSA colonisation, in contrast to known MRSA-positive infants.
  
  
  CONCLUSIONS
  The integration of epidemiological (temporal, spatial) and genomic data enabled the phylogenetic testing of several hypotheses on specific MRSA transmission routes within a neonatal intensive-care unit. The pronounced risk of transmission emanating from undetected MRSA carriers suggested that increasing the frequency or speed of microbiological diagnostics could help to reduce transmission of MRSA.
authors: Department of Infectious Diseases, Unit of Nosocomial Infections, Robert Koch Institute, Wernigerode, Germany. nuebelu@rki.de
authors: Ulrich
authors: U
authors: Nübel
authors: Matthias
authors: M
authors: Nachtnebel
authors: Gerhard
authors: G
authors: Falkenhorst
authors: Justus
authors: J
authors: Benzler
authors: Jochen
authors: J
authors: Hecht
authors: Michael
authors: M
authors: Kube
authors: Felix
authors: F
authors: Bröcker
authors: Karin
authors: K
authors: Moelling
authors: Christoph
authors: C
authors: Bührer
authors: Petra
authors: P
authors: Gastmeier
authors: Brar
authors: B
authors: Piening
authors: Michael
authors: M
authors: Behnke
authors: Manuel
authors: M
authors: Dehnert
authors: Franziska
authors: F
authors: Layer
authors: Wolfgang
authors: W
authors: Witte
authors: Tim
authors: T
authors: Eckmanns
mesh_terms: D016022:Case-Control Studies; D005260:Female; D014644:Genetic Variation; D016680:Genome, Bacterial / Q000235:genetics; D023281:Genomics; D006801:Humans; D007231:Infant, Newborn; D007363:Intensive Care Units, Neonatal; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification / Q000235:genetics* / Q000502:physiology*; D010802:Phylogeny; D012307:Risk Factors; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission*
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