title: Genomic diversity within the Enterobacter cloacae complex.
abstract: BACKGROUND
  Isolates of the Enterobacter cloacae complex have been increasingly isolated as nosocomial pathogens, but phenotypic identification of the E. cloacae complex is unreliable and irreproducible. Identification of species based on currently available genotyping tools is already superior to phenotypic identification, but the taxonomy of isolates belonging to this complex is cumbersome.
  
  
  RESULTS
  This study shows that multilocus sequence analysis and comparative genomic hybridization based on a mixed genome array is a powerful method for studying species assignment within the E. cloacae complex. The E. cloacae complex is shown to be evolutionarily divided into two clades that are genetically distinct from each other. The younger first clade is genetically more homogenous, contains the Enterobacter hormaechei species and is the most frequently cultured Enterobacter species in hospitals. The second and older clade consists of several (sub)species that are genetically more heterogeneous. Genetic markers were identified that could discriminate between the two clades and cluster 1.
  
  
  CONCLUSIONS
  Based on genomic differences it is concluded that some previously defined (clonal and heterogenic) (sub)species of the E. cloacae complex have to be redefined because of disagreements with known or proposed nomenclature. However, further improved identification of the redefined species will be possible based on novel markers presented here.
authors: Department of Medical Microbiology, University Medical Centre Utrecht, Utrecht, The Netherlands.
authors: Armand
authors: A
authors: Paauw
authors: Martien P M
authors: MP
authors: Caspers
authors: Frank H J
authors: FH
authors: Schuren
authors: Maurine A
authors: MA
authors: Leverstein-van Hall
authors: Alexis
authors: A
authors: Delétoile
authors: Roy C
authors: RC
authors: Montijn
authors: Jan
authors: J
authors: Verhoef
authors: Ad C
authors: AC
authors: Fluit
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D016972:Enterobacter cloacae / Q000145:classification / Q000235:genetics*; D014644:Genetic Variation; D016680:Genome, Bacterial; D005838:Genotype; D009693:Nucleic Acid Hybridization; D010802:Phylogeny; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial