genomic diversity within the enterobacter cloacae complex肠杆菌属内基因多样性泄殖腔复杂.pdfVIP

Genomic Diversity within the Enterobacter cloacae Complex 1 2 2 1 Armand Paauw *, Martien P. M. Caspers , Frank H. J. Schuren , Maurine A. Leverstein-van Hall , Alexis ´ 3 2 1 1 Deletoile , Roy C. Montijn , Jan Verhoef , Ad C. Fluit ´ 1 Department of Medical Microbiology, University Medical Centre Utrecht, Utrecht, The Netherlands, 2 TNO Department of Microbiology, Zeist, The Netherlands, 3 Unite ´ ´ ` Biodiversite des Bacteries Pathogenes Emergentes, Institut Pasteur, Paris, France 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. Methodology/Principal Findings: 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 cu