Subinhibitory bismuth-thiols reduce virulence of Pseudomonas aeruginosa.
Pseudomonas aeruginosa is a common pathogen in mechanically ventilated patients and produces a wide array of virulence factors. Bismuth-thiols (BTs) are active in vitro against all bacterial lung pathogens, including P. aeruginosa. The objective of these studies was to examine the biochemical and morphologic effects of sublethal BT concentrations on P. aeruginosa and to evaluate virulence in cell culture. Bismuth-dimercaprol, at a fraction of the minimal inhibitory concentration, reduced alginate expression by 67% in P. aeruginosa, whereas subinhibitory bismuth-ethanedithiol (BisEDT) reduced alginate by 92% in P. syringae. BisEDT effects on lipopolysaccharide content and type III secreted cytoxins were examined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Subinhibitory BisEDT reduced cell-associated lipopolysaccharide, and inhibited processing of the secreted cytotoxic protein ExoU. BisEDT-induced outer membrane blebbing and aggregation of cytoplasmic material was noted in electron microscopy. Virulence of P. aeruginosa was assessed by adherence to epithelial cells and sensitivity to serum killing. BisEDT inhibited adherence of P. aeruginosa to 16HBE14o- cells by 28% and to a collagen matrix by 53%. BisEDT-treated bacteria were also 100-fold more sensitive to serum bactericidal activity. In summary, low BT concentrations affect P. aeruginosa in a variety of ways, the combination of which may help prevent or resolve respiratory tract infection.
Wu
Chieh-Liang
CL
CardioPulmonary Research Institute, Division of Pulmonary and Critical Care Medicine, Winthrop-University Hospital, SUNY School of Medicine at Stony Brook, Mineola, New York 11501, USA.
Domenico
Philip
P
Hassett
Daniel J
DJ
Beveridge
Terry J
TJ
Hauser
Alan R
AR
Kazzaz
Jeffrey A
JA
D001422:Bacterial Adhesion / Q000187:drug effects; D001729:Bismuth / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel; D008826:Microbial Sensitivity Tests; D008854:Microscopy, Electron; D011499:Protein Processing, Post-Translational; D011550:Pseudomonas aeruginosa / Q000472:pathogenicity* / Q000648:ultrastructure; D013438:Sulfhydryl Compounds / Q000494:pharmacology*; D014774:Virulence / Q000187:drug effects*
D013438:Sulfhydryl Compounds; D001729:Bismuth