Papel del "quorum sensing" y del hierro en la formación de biofilms y en la producción de otros potenciales factores de virulencia de Stenotrophomonas maltophilia
In Stenotrophomonas maltophilia the quorum-sensing (QS) system is mediated by\nDSF, which synthesis depends on rpfF. Studies were done on K279a and its rpfF\nmutant, on Fur (?ferric uptake regulator?) mutants obtained for the first time in S.\nmaltophilia in this work, and on 63 local isolates recov...
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| Formato: | Tesis doctoral acceptedVersion |
| Lenguaje: | Español |
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Facultad de Farmacia y Bioquímica
2015
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| Acceso en línea: | http://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=posgraafa&cl=CL1&d=HWA_1029 http://repositoriouba.sisbi.uba.ar/gsdl/collect/posgraafa/index/assoc/HWA_1029.dir/1029.PDF |
| Aporte de: |
| Sumario: | In Stenotrophomonas maltophilia the quorum-sensing (QS) system is mediated by\nDSF, which synthesis depends on rpfF. Studies were done on K279a and its rpfF\nmutant, on Fur (?ferric uptake regulator?) mutants obtained for the first time in S.\nmaltophilia in this work, and on 63 local isolates recovered from patients with deviceassociated\ninfections. The genotyping of local isolates showed a great diversity,\nsuggesting that most of the nosocomial episodes were independent. All the isolates but\none produced strong biofilms. All o them were lipolytic, proteolytic and produced\ncatechol-type siderophores. In the iron acquisition system of S. maltophilia two outer\nmembrane receptors FepA and CirA, regulated by Fur-Fe2+, are responsible for the\nuptake of the siderophore. The isoenzyme Mn-SOD was the only isoenzyme detected\nin planktonic cultures and biofilms of K279a, and it was regulated by Fur-Fe2+. In the\nGalleria mellonella virulence model the lethal effect correlated with resistance to\noxidative stress. In conclusion, in S. maltophilia biofilm formation and potential\nvirulence factors production are positively regulated by QS, and negatively regulated by\niron levels through the Fur system. Furthermore, the relation between the two systems\nwas demonstrated by the first time. |
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