%0 Journal Article
%T Klebsiella pneumoniae triggers a cytotoxic effect on airway epithelial cells
%A Victoria Cano
%A David Moranta
%A Enrique Llobet-Brossa
%A Jos¨¦ Bengoechea
%A Junkal Garmendia
%J BMC Microbiology
%D 2009
%I BioMed Central
%R 10.1186/1471-2180-9-156
%X The interaction between Klebsiella pneumoniae and cultured airway epithelial cells was analysed. K. pneumoniae infection triggered cytotoxicity, evident by cell rounding and detachment from the substrate. This effect required the presence of live bacteria and of capsule polysaccharide, since it was observed with isolates expressing different amounts of capsule and/or different serotypes but not with non-capsulated bacteria. Cytotoxicity was analysed by lactate dehydrogenase and formazan measurements, ethidium bromide uptake and analysis of DNA integrity, obtaining consistent and complementary results. Moreover, cytotoxicity of non-capsulated strains was restored by addition of purified capsule during infection. While a non-capsulated strain was avirulent in a mouse infection model, capsulated K. pneumoniae isolates displayed different degrees of virulence.Our observations allocate a novel role to K. pneumoniae capsule in promotion of cytotoxicity. Although this effect is likely to be associated with virulence, strains expressing different capsule levels were not equally virulent. This fact suggests the existence of other bacterial requirements for virulence, together with capsule polysaccharide.Klebsiella pneumoniae is the most common Gram-negative bacterium causing community-acquired pneumonia and up to 5% of community-acquired urinary tract infections [1-3]. Community-acquired pneumonia is a very severe illness with a rapid onset, and despite the availability of an adequate antibiotic regimen, the outcome is often fatal. The observed mortality rates are about 50% [4]. Capsule polysaccharide (CPS), siderophores, lipopolysaccharide (LPS) and adhesins are virulence factors identified for this pathogen. However, most of the studies have focused on the role of CPS in Klebsiella virulence. Early studies suggested that an extracellular toxic complex mainly composed of CPS triggers extensive lung tissue damage [5,6] and data indicate that there might be a correlation betw
%U http://www.biomedcentral.com/1471-2180/9/156