title: A heat-stable cytotoxic factor produced by Achromobacter xylosoxidans isolated from Brazilian patients with CF is associated with in vitro increased proinflammatory cytokines.
abstract: BACKGROUND
  Recently, Achromobacter xylosoxidans has been related to chronic lung diseases in patients suffering from cystic fibrosis (CF), but its involvement has not been elucidated. Some virulence properties of A. xylosoxidans isolated from Brazilian patients with CF were revealed in this work.
  
  
  METHODS
  This study examined the production of a cytotoxic factor of A. xylosoxidans capable of stimulating the secretion of inflammatory cytokines (IL-6 and IL-8) from lung mucoepidermoid carcinoma cells (NCI-H292). The cytokines were measured using enzyme-linked immunosorbent (ELISA) assays. To investigate whether the cytotoxic factors may be endotoxins, they were treated with polymyxin B.
  
  
  RESULTS
  The culture supernatants of all A. xylosoxidans produced a heat stable, active cytotoxin in NCI-H292 cells capable of leading to intracellular vacuoles and subsequent cell contact loss, chromatin condensation, a picnotic nucleus and cell death. There was a higher concentration of proinflammatory cytokines in the NCI-H292 cells after 24 h of incubation, with the fraction greater than 50 kDa from the culture supernatant. The cytotoxin activity remained even after treatment with polymyxin B, which suggested that the release of IL-6 and IL-8 was not stimulated by lipopolysaccharide (LPS).
  
  
  CONCLUSIONS
  The cytotoxic factor produced by A. xylosoxidans may represent an important virulence factor, which when associated with CF chronic lung inflammation, may cause tissue damage and decline of lung function.
authors.affiliation: Department of Genetics, Evolution and Bioagents, Biology Institute, State University of Campinas (UNICAMP), Campinas, SP, Brazil. rebecapmantovani@yahoo.com.br
authors.forename: Rebeca P
authors.initials: RP
authors.lastname: Mantovani
authors.forename: Carlos E
authors.initials: CE
authors.lastname: Levy
authors.forename: Tomomasa
authors.initials: T
authors.lastname: Yano
mesh_terms: D042441:Achromobacter denitrificans / Q000276:immunology / Q000378:metabolism* / Q000472:pathogenicity; D001938:Brazil; D018277:Carcinoma, Mucoepidermoid; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000276:immunology; D017077:Culture Media, Conditioned / Q000633:toxicity; D003550:Cystic Fibrosis / Q000276:immunology / Q000382:microbiology*; D004731:Endotoxins / Q000276:immunology / Q000378:metabolism*; D016905:Gram-Negative Bacterial Infections / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D015850:Interleukin-6 / Q000276:immunology / Q000378:metabolism*; D016209:Interleukin-8 / Q000276:immunology / Q000378:metabolism*; D011014:Pneumonia / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D013183:Sputum / Q000276:immunology / Q000382:microbiology; D014774:Virulence
chemical_list: C508606:CXCL8 protein, human; D017077:Culture Media, Conditioned; D004731:Endotoxins; C508600:IL6 protein, human; D015850:Interleukin-6; D016209:Interleukin-8