Publications by authors named "Veronica Relling"

The number and type of outer membrane (OM) channels responsible for carbapenem uptake in are still not well defined. Here, we addressed these questions by using as a model species and a combination of methodologies aimed to characterize OM channels in their original membrane environment. Kinetic and competition analyses of imipenem (IPM) uptake by whole cells allowed us to identify different carbapenem-specific OM uptake sites.

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We described previously the presence in Acinetobacter baumannii of a novel outer membrane (OM) protein, CarO, which functions as an L-ornithine OM channel and whose loss was concomitant with increased carbapenem resistance among clonally related nosocomial isolates of this opportunistic pathogen. Here, we describe the existence of extensive genetic diversity at the carO gene within the A. baumannii clinical population.

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We previously associated the emergence of carbapenem resistance in Acinetobacter baumannii with the loss of an outer membrane (OM) protein designated CarO. CarO was found essential for L-ornithine uptake: CarO-deficient strains were specifically impaired to grow only on L-ornithine, and failed to incorporate L-[(14)C] ornithine from the medium. L-arginine, and histidine and lysine to a lower extent, could effectively compete for L-[(14)C] ornithine uptake.

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Xanthan-deficient mutants of Xanthomonas axonopodis pv. citri, the bacterium responsible for citrus canker, were generated by deletion and marker exchange of the region encoding the carboxy-terminal end of the first glycosyltransferase, GumD. Mutants of gumD did not produce xanthan and remained pathogenic in citrus plants to the same extent as wild-type bacteria.

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