Infecto-contagiosas/Epidemias

Os pesquisadores utilizaram marcadores fluorescentes de isotiocianato para rastreamento de S.aureus e analisaram a relação entre a bactéria e o endotélio vascular de arteríolas, capilares e vênulas da região dorsal de hamsters tratados ou não tratados com fator de necrose tumoral (TNF).

Durante os primeiros 20 minutos da injeção do marcador fluorescente, mais de 99% das bactérias foi removida da corrente sangüínea microvascular. Por outro lado, bactérias isoladas e grupos de bactérias foram capazes de aderir à superfície endotelial de vênulas pós-capilares e a capilares nutritivos. Aderência bacteriana ao endotélio arteriolar raramente foi observada. Tratamento com TNF acelerou significativamente o clearance bacteriano e resultou em significante aumento da aderência bacteriana em endotélio venular, mas não ao endotélio arteriolar ou capilar, indicando que o endotélio venular é a estrutura alvo para recrutamento bacteriano.

Intravital Fluorescence Microscopy: A Novel Tool for the Study of the Interaction of Staphylococcus aureus with the Microvascular Endothelium In Vivo - The Journal of Infectious Diseases; 2005; 191(3):435-443

Intravital Fluorescence Microscopy: A Novel Tool for the Study of the Interaction of Staphylococcus aureus with the Microvascular Endothelium In Vivo

Matthias W. Laschke,^1,a Sylvain Kerdudou,^2,a Mathias Herrmann,² and Michael D. Menger¹

Institutes for ¹Clinical and Experimental Surgery and ²Medical Microbiology and Hygiene, University of Saarland, Homburg/Saar, Germany

Background.     The ability of Staphylococcus aureus to adhere to endothelial cells is a major prerequisite for the tissue-invasive stage of bacterial infection.      Methods.     To develop a model for the study of endothelial attachment and detachment kinetics of S. aureus within the host's microvasculature in vivo, we labeled inactivated staphylococci with fluorescein isothiocyanate and investigated their interaction with the vascular endothelium of arterioles, capillaries, and venules in the dorsal skin-fold chamber of untreated and tumor necrosis factor (TNF)treated hamsters by use of intravital fluorescence microscopy.      Results.     During the first 20 min after injection, >99% of the bacteria were removed from the microvascular bloodstream. In parallel, single bacteria and bacterial clusters adhered to the endothelial lining of postcapillary venules and to nutritive capillaries. Bacterial adherence to the endothelium of arterioles was only rarely observed. TNF- treatment significantly accelerated bacterial clearance and resulted in a significant increase of venular, but not arteriolar and capillary, bacterial adherence, indicating the venular endothelium to be the target structure for bacterial recruitment.      Conclusion.     The insights into host-pathogen interaction gained with this new in vivo model offer highly promising novel aspects of the understanding of infections caused by S. aureus.

     Received 7 June 2004; accepted 19 August 2004; electronically published 28 December 2004.
     Financial support: Deutsche Forschungsgemeinschaft (priority program 1130); Medical Faculty of the University of Saarland (program HOMFOR C 2003/11).
     ^a M.W.L. and S.K. contributed equally to the study.