title: Study of an outbreak of Enterobacter cloacae sepsis in a neonatal intensive care unit: the application of epidemiologic chromosome profiling by pulsed-field gel electrophoresis.
abstract: OBJECTIVE
  From October 1996 to March 1997, a cluster of 11 cases of neonatal sepsis caused by Enterobacter cloacae with similar antimicrobial susceptibility patterns occurred in a neonatal intensive care unit. This outbreak prompted an investigation.
  
  
  METHODS
  Twelve isolates obtained from 6 neonatal patients who developed E cloacae sepsis during the outbreak were analyzed. Four E cloacae isolates from 2 preterm neonates without E cloacae infection on the same ward, and 1 isolate from the hands of a nurse, were also examined. No E cloacae were isolated from the environment. Bacterial DNA digested with XbaI or NotI was analyzed with pulsed-field gel electrophoresis.
  
  
  RESULTS
  Three distinct banding patterns were identified by pulsed-field gel electrophoresis. Of the 6 preterm infants with sepsis, strain I was identified in 1, strain II in 2, a mixed infection of strains I and II in 2, and strain III was found in only 1 infant. An isolate from the hands of a nurse was identified as strain II, as were the 4 isolates from the 2 preterm neonates without E cloacae infection. Thus, this outbreak of sepsis was caused by 2 genotypes of E cloacae.
  
  
  CONCLUSIONS
  This study demonstrates that pulsed-field gel electrophoresis with restriction enzyme digestion is a valuable tool for genetic characterization of multidrug-resistant E cloacae strains during outbreaks.
authors.affiliation: Division of Infectious Diseases, Department of Pediatrics, Chung Shan Medical and Dental College Hospital, Taichung, Taiwan.
authors.forename: Shu-Chih
authors.initials: SC
authors.lastname: Liu
authors.forename: Hsieh-Shong
authors.initials: HS
authors.lastname: Leu
authors.forename: Muh-Yong
authors.initials: MY
authors.lastname: Yen
authors.forename: Ping-Ing
authors.initials: PI
authors.lastname: Lee
authors.forename: Ming-Chih
authors.initials: MC
authors.lastname: Chou
mesh_terms: D015373:Bacterial Typing Techniques; D002876:Chromosomes, Bacterial / Q000235:genetics*; D004196:Disease Outbreaks; D024881:Drug Resistance, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D016972:Enterobacter cloacae / Q000235:genetics* / Q000302:isolation & purification*; D004756:Enterobacteriaceae Infections / Q000453:epidemiology / Q000382:microbiology; D005260:Female; D005838:Genotype; D006801:Humans; D007231:Infant, Newborn; D007363:Intensive Care Units, Neonatal; D008297:Male; D012307:Risk Factors; D018805:Sepsis / Q000453:epidemiology* / Q000382:microbiology*