RESUMO
Bacterial adherence is a complex phenomenon involving specific interactions between receptors, including matricial fibronectin, and bacterial ligands. We show here that fibronectin and outer membrane proteins of Pseudomonas fluorescens were able to inhibit adherence of P. fluorescens to fibronectin-coated wells. We identified at least six fibronectin-binding proteins with molecular masses of 70, 55, 44, 37, 32 and 28 kDa. The presence of native (32 kDa) and heat-modified forms (37 kDa) of OprF was revealed by immuno-analysis and the 44-kDa band was composed of three proteins, their N-terminal sequences showing homologies with Pseudomonas aeruginosa porins (OprD, OprE1 and OprE3).
Assuntos
Proteínas da Membrana Bacteriana Externa , Proteínas de Bactérias , Fibronectinas/metabolismo , Porinas/metabolismo , Pseudomonas fluorescens/metabolismo , Aderência Bacteriana , Western Blotting , Porinas/genética , Homologia de Sequência de AminoácidosRESUMO
The aim of this study was to evaluate the effect of antibiotics at subminimal inhibitory concentrations (sub-MIC) on fluorescent pseudomonas adherence to A549 pneumocyte cells. Pseudomonas fluorescens MF0 isolated from contaminated raw milk and Pseudomonas aeruginosa NK125502 isolated from a cystic fibrosis patient's lung adhered to A549 cells. As previously shown for P. aeruginosa, P. fluorescens bound to A549 cells in a dose-dependent manner over a wide range of bacterial concentrations. Bacterial growth in the presence of polymyxin B or gentamicin at MIC/2 had no effect on the adherence of NK125502 and MF0 to A549 cells. Instead, MIC/2 and MIC/8 of cefsulodin or chloramphenicol decreased the adherence of the two strains. A decrease in MF0 adherence was also observed with cefsulodin at MIC/32. We conclude that, in addition to their antibacterial activity, cefsulodin and chloramphenicol could be effective in preventing Pseudomonas adherence to respiratory epithelium.
Assuntos
Antibacterianos/farmacologia , Aderência Bacteriana/efeitos dos fármacos , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/microbiologia , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas fluorescens/efeitos dos fármacos , Alvéolos Pulmonares/efeitos dos fármacos , Alvéolos Pulmonares/microbiologia , Animais , Cefsulodina/farmacologia , Linhagem Celular , Cloranfenicol/farmacologia , Gentamicinas/farmacologia , Humanos , Polimixina B/farmacologia , Pseudomonas aeruginosa/fisiologia , Pseudomonas fluorescens/fisiologia , Alvéolos Pulmonares/citologiaRESUMO
Pseudomonas aeruginosa adherence is a complex phenomenon largely mediated by pili involving specific receptor-ligand interactions. Anti-fibronectin antibodies as well as plasmatic fibronectin are able to inhibit P. aeruginosa adherence onto A549 cells showing that matricial fibronectin is an actual receptor for this bacterium. Experiments performed in vitro with human plasmatic fibronectin used as receptor and outer membrane proteins of P. aeruginosa as ligands show the presence of four fibronectin-binding proteins. These proteins with molecular mass of 70 +/- 2, 60 +/- 2, 48 +/- 2 and 36 +/- 1 kDa should be adhesins of P. aeruginosa on epithelial cell matrix in a non-pilus mediated adherence.