title: The Prevalence and Molecular Epidemiology of Multidrug-Resistant Enterobacteriaceae Colonization in a Pediatric Intensive Care Unit.
abstract: OBJECTIVE
  To determine the prevalence and acquisition of extended-spectrum β-lactamases (ESBLs), plasmid-mediated AmpCs (pAmpCs), and carbapenemases ("MDR Enterobacteriaceae") colonizing children admitted to a pediatric intensive care unit (PICU).
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  40-bed PICU.
  
  
  METHODS
  Admission and weekly thereafter rectal surveillance swabs were collected on all pediatric patients during a 6-month study period. Routine phenotypic identification and antibiotic susceptibility testing were performed. Enterobacteriaceae displaying characteristic resistance profiles underwent further molecular characterization to identify genetic determinants of resistance likely to be transmitted on mobile genetic elements and to evaluate relatedness of strains including DNA microarray, multilocus sequence typing, repetitive sequence-based PCR, and hsp60 sequencing typing.
  
  
  RESULTS
  Evaluating 854 swabs from unique children, the overall prevalence of colonization with an MDR Enterobacteriaceae upon admission to the PICU based on β-lactamase gene identification was 4.3% (n=37), including 2.8% ESBLs (n=24), 1.3% pAmpCs (n=11), and 0.2% carbapenemases (n=2). Among 157 pediatric patients contributing 603 subsequent weekly swabs, 6 children (3.8%) acquired an incident MDR Enterobacteriaceae during their PICU stay. One child acquired a pAmpC (E. coli containing bla DHA) related to an isolate from another patient.
  
  
  CONCLUSIONS
  Approximately 4% of children admitted to a PICU were colonized with MDR Enterobacteriaceae (based on β-lactamase gene identification) and an additional 4% of children who remained in the PICU for at least 1 week acquired 1 of these organisms during their PICU stay. The acquired MDR Enterobacteriaceae were relatively heterogeneous, suggesting that a single source was not responsible for the introduction of these resistance mechanisms into the PICU setting.
authors: 1Division of Medical Microbiology,Johns Hopkins Medical Institutions,Baltimore,Maryland,USA.
authors: Nuntra
authors: N
authors: Suwantarat
authors: 3Section of Pediatric Infectious Diseases,Rush University Medical Center,Chicago,Illinois,USA.
authors: Latania K
authors: LK
authors: Logan
authors: 1Division of Medical Microbiology,Johns Hopkins Medical Institutions,Baltimore,Maryland,USA.
authors: Karen C
authors: KC
authors: Carroll
authors: 4Louis Stokes Cleveland Department of Veterans' Affairs Medical Center,Cleveland,Ohio,USA.
authors: Robert A
authors: RA
authors: Bonomo
authors: 1Division of Medical Microbiology,Johns Hopkins Medical Institutions,Baltimore,Maryland,USA.
authors: Patricia J
authors: PJ
authors: Simner
authors: 6Department of Molecular Biology and Microbiology,Case Western Reserve University School of Medicine,Cleveland,Ohio,USA.
authors: Susan D
authors: SD
authors: Rudin
authors: 8Division of Pediatric Infectious Diseases,Johns Hopkins University School of Medicine,Baltimore,Maryland,USA.
authors: Aaron M
authors: AM
authors: Milstone
authors: 1Division of Medical Microbiology,Johns Hopkins Medical Institutions,Baltimore,Maryland,USA.
authors: Tsigereda
authors: T
authors: Tekle
authors: 1Division of Medical Microbiology,Johns Hopkins Medical Institutions,Baltimore,Maryland,USA.
authors: Tracy
authors: T
authors: Ross
authors: 8Division of Pediatric Infectious Diseases,Johns Hopkins University School of Medicine,Baltimore,Maryland,USA.
authors: Pranita D
authors: PD
authors: Tamma
mesh_terms: D000293:Adolescent; D001426:Bacterial Proteins / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D004269:DNA, Bacterial / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004755:Enterobacteriaceae / Q000302:isolation & purification*; D004756:Enterobacteriaceae Infections / Q000453:epidemiology*; D004926:Escherichia coli / Q000235:genetics; D005243:Feces / Q000382:microbiology; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D015278:Intensive Care Units, Pediatric; D008297:Male; D008396:Maryland; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology / Q000379:methods*; D058885:Multilocus Sequence Typing; D011446:Prospective Studies; D055815:Young Adult; D001618:beta-Lactamases / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; C048795:AmpC beta-lactamases; D001618:beta-Lactamases; C063912:carbapenemase