Penetration of clinical isolates of Pseudomonas aeruginosa through MDCK epithelial cell monolayers

J Infect Dis. 2000 Feb;181(2):765-9. doi: 10.1086/315276.


Pseudomonas aeruginosa causes both invasive (bacteremic) and chronic noninvasive infections. A simple in vitro system to screen P. aeruginosa clinical isolates for their capacity to penetrate MDCK cell monolayers has been developed. By means of this system, P. aeruginosa clinical isolates, including 32 blood and 45 respiratory isolates, were examined. When monolayers were infected with 3.5x107 cfu of bacteria, significantly more blood (93.7%) than respiratory (54.4%) isolates (P<.001) were detected in the basolateral medium after 3 h. Penetration ability was usually independent of cytotoxicity. Only 8 (4 blood and 4 respiratory) isolates were cytotoxic, possessed exoU, and passed through the monolayer after epithelial cell death, associated with a marked drop in transepithelial electrical resistance. Conversely, noncytotoxic isolates with high penetration ability but without severe epithelial damage were invasive. This system is well suited for screening clinical isolates and their mutants for specific genes conferring the invasiveness phenotype.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacteriological Techniques
  • Cell Line
  • Cell Survival
  • Dogs
  • Epithelial Cells / cytology
  • Epithelial Cells / microbiology*
  • Escherichia coli / physiology
  • Humans
  • L-Lactate Dehydrogenase / metabolism
  • Pseudomonas Infections / microbiology
  • Pseudomonas aeruginosa / pathogenicity*
  • Pseudomonas aeruginosa / physiology


  • L-Lactate Dehydrogenase