title: Acinetobacter baumannii invades epithelial cells and outer membrane protein A mediates interactions with epithelial cells.
abstract: BACKGROUND
  Acinetobacter baumannii is a nosocomial pathogen of increasing importance, but the pathogenic mechanism of this microorganism has not been fully explored. This study investigated the potential of A. baumannii to invade epithelial cells and determined the role of A. baumannii outer membrane protein A (AbOmpA) in interactions with epithelial cells.
  
  
  RESULTS
  A. baumannii invaded epithelial cells by a zipper-like mechanism, which is associated with microfilament- and microtubule-dependent uptake mechanisms. Internalized bacteria were located in the membrane-bound vacuoles. Pretreatment of recombinant AbOmpA significantly inhibited the adherence to and invasion of A. baumannii in epithelial cells. Cell invasion of isogenic AbOmpA- mutant significantly decreased as compared with wild-type bacteria. In a murine pneumonia model, wild-type bacteria exhibited a severe lung pathology and induced a high bacterial burden in blood, whereas AbOmpA- mutant was rarely detected in blood.
  
  
  CONCLUSIONS
  A. baumannii adheres to and invades epithelial cells. AbOmpA plays a major role in the interactions with epithelial cells. These findings contribute to the understanding of A. baumannii pathogenesis in the early stage of bacterial infection.
authors.affiliation: Department of Microbiology, Kyungpook National University School of Medicine, Daegu, Korea. chchoi@knu.ac.kr
authors.forename: Chul Hee
authors.initials: CH
authors.lastname: Choi
authors.forename: Jun Sik
authors.initials: JS
authors.lastname: Lee
authors.forename: Yoo Chul
authors.initials: YC
authors.lastname: Lee
authors.forename: Tae In
authors.initials: TI
authors.lastname: Park
authors.forename: Je Chul
authors.initials: JC
authors.lastname: Lee
mesh_terms: D000151:Acinetobacter Infections / Q000378:metabolism*; D040981:Acinetobacter baumannii / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism*; D018407:Bacterial Physiological Phenomena / Q000187:drug effects; D002460:Cell Line; D015638:Cytochalasin D / Q000494:pharmacology; D004847:Epithelial Cells / Q000382:microbiology*; D006367:HeLa Cells; D006801:Humans; D009154:Mutation; D014747:Vinblastine / Q000494:pharmacology
chemical_list: D001425:Bacterial Outer Membrane Proteins; C078167:OMPA outer membrane proteins; D015638:Cytochalasin D; D014747:Vinblastine