title: Carbapenem resistance confers to Klebsiella pneumoniae strains an enhanced ability to induce infection and cell death in epithelial tissue-specific in vitro models.
abstract: BACKGROUND
  Carbapenem-resistant Klebsiella pneumoniae strains (KPC-Kp) are emerging worldwide causing different nosocomial infections including those of the urinary tract, lung or skin wounds. For these strains, the antibiotic treatment is limited to only few choices including colistin, whose continuous use led to the emergence of carbapenem-resistant KPC-Kp strains resistant also to this treatment (KPC-Kp Col-R).
  
  
  OBJECTIVE
  Very little is known about the capacity of the different strains of KPC-Kp to invade the epithelial cells in vitro. To verify if the acquisition of carbapenem-resistant and the colistin-resistant phenotypes are correlated with a different ability to infect a series of epithelial cell lines of various tissutal origin and with a different capacity to induce cellular death.
  
  
  METHODS
  We used Klebsiella pneumoniae (KP), KPC-Kp and KPC-Kp Col-R strains, isolated from different patients carrying various tissue-specific infections, to infect a series of epithelial cell lines of different tissutal origin. The invasive capacity of the strains and the extent and characteristics of the cell damage and death induced by the bacteria were evaluated and compared.
  
  
  CONCLUSIONS
  Our results show that both KPC-Kp and KPC-Kp Col-R display a greater ability to infect the epithelial cells, with respect to KP, and that the bacterial cell invasion results in a nonprogrammed cell death.
authors.forename: Laura
authors.initials: L
authors.lastname: Leone
authors.affiliation: 2Azienda Ospedaliera S. Andrea, Rome, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Raffa
authors.affiliation: 2Azienda Ospedaliera S. Andrea, Rome, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Martinelli
authors.affiliation: 2Azienda Ospedaliera S. Andrea, Rome, Italy.
authors.forename: Maria Rosaria
authors.initials: MR
authors.lastname: Torrisi
authors.affiliation: 2Azienda Ospedaliera S. Andrea, Rome, Italy.
authors.forename: Iolanda
authors.initials: I
authors.lastname: Santino
mesh_terms: D016923:Cell Death; D002460:Cell Line; D004705:Endocytosis; D004847:Epithelial Cells / Q000382:microbiology* / Q000502:physiology*; D006801:Humans; D007710:Klebsiella Infections / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000302:isolation & purification / Q000502:physiology*; D018440:beta-Lactam Resistance
keywords: KPC-Kp; Klebsiella pneumoniae; cell death; epithelial cell lines; infection ability