Enterobacter cloacae complex: Clinical impact and emerging antibiotic resistance

Maria Lina Mezzatesta, Floriana Gona, Stefania Stefani

Research output: Contribution to journalArticlepeer-review


Species of the Enterobacter cloacae complex are widely encountered in nature, but they can act as pathogens. The biochemical and molecular studies on E. cloacae have shown genomic heterogeneity, comprising six species: Enterobacter cloacae, Enterobacter asburiae, Enterobacter hormaechei, Enterobacter kobei, Enterobacter ludwigii and Enterobacter nimipressuralis, E. cloacae and E. hormaechei are the most frequently isolated in human clinical specimens. Phenotypic identification of all species belonging to this taxon is usually difficult and not always reliable; therefore, molecular methods are often used. Although the E. cloacae complex strains are among the most common Enterobacter spp. causing nosocomial bloodstream infections in the last decade, little is known about their virulence-associated properties. By contrast, much has been published on the antibiotic-resistance features of these microorganisms. In fact, they are capable of overproducing AmpC -lactamases by derepression of a chromosomal gene or by the acquisition of a transferable ampC gene on plasmids conferring the antibiotic resistance. Many other resistance determinants that are able to render ineffective almost all antibiotic families have been recently acquired. Most studies on antimicrobial susceptibility are focused on E. cloacae, E. hormaechei and E. asburiae; these studies reported small variations between the species, and the only significant differences had no discriminating features.

Original languageEnglish
Pages (from-to)887-902
Number of pages16
JournalFuture Microbiology
Issue number7
Publication statusPublished - Jul 2012


  • antibiotic resistance
  • E. cloacae complex
  • Enterobacter asburiae
  • Enterobacter cloacae
  • Enterobacter hormaechei
  • Enterobacter kobei
  • Enterobacter ludwigii
  • Enterobacter nimipressuralis

ASJC Scopus subject areas

  • Microbiology
  • Microbiology (medical)


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