B-277. Systematic Analysis of Uropathogenic Escherichia coli Metabolism during Growth in Human Urine

C. J. Alteri, D. J. Reiss, H. L. T. Mobley;
Univ. of Michigan Med. Sch., Ann Arbor, MI.

Microbial pathogenesis studies mainly encompass dissection of virulence properties such as the bacterium’s ability to elaborate toxins, adhere to and invade host cells, cause tissue damage, or otherwise disrupt normal host immune and cellular functions. In contrast, bacterial metabolism during the infectious process represents an area that has received much less scrutiny. In this study, we used comparative proteomics to investigate the expression of uropathogenic Escherichia coli (UPEC) cytoplasmic proteins during growth in the urinary tract environment to better understand bacterial metabolism during infection. Using two-dimensional fluorescence difference in gel electrophoresis (2D-DIGE) and tandem mass spectrometry we found that UPEC differentially expresses 84 proteins between growth in LB medium and growth in human urine (P<0.005). For example, the glycolytic enzyme triosephosphate isomerase TpiA was induced 4.58-fold and the pentose phosphate pathway enzyme transaldolase TalA was induced 5.66-fold in urine. In addition to these central metabolism enzymes, other up-regulated proteins include those involved in the uptake and catabolism of pentose sugars such as an arabinose-binding protein AraF and xylose isomerase XylA that were induced 2.02- and 5.25-fold, respectively. Expression of N-acetylneuraminate lyase NanA, that was induced 3.64-fold, shows that UPEC catabolize the amino sugar sialic acid during growth in the urinary tract environment. Proteins involved in the metabolism of amino acids and polyamines were also found to be induced in urine; ArgG, SerA and agmatinase SpeB were up-regulated 3.41-fold, 4.44-fold, and 4.06-fold, respectively. Additional proteins induced during growth in human urine include dipeptide and oligopeptide-binding proteins, the PTS fructose-specific IIA/FPr component, and two peptidyl-prolyl isomerases. These findings suggest that these bacteria simultaneously utilize a dynamic array of metabolic and transport functions to efficiently grow in human urine and also provide the foundation for a systematic analysis of UPEC metabolism during urinary tract infection.