Preferential Use of Central Metabolism In Vivo Reveals a Nutritional Basis for Polymicrobial Infection
Figure 2
Glycolysis is required for P. mirabilis but is dispensible for E. coli during experimental urinary tract infection.
In vivo competitive indices (CI) were determined following co-challenge infections of susceptible female CBA/J mice with a 1∶1 ratio of either wild-type (A) E. coli CFT073 or (B) P. mirabilis HI4320 and their respective glycolysis mutant strains. E. coli were recovered at 48 h post-inoculation (hpi). P. mirabilis was recovered at 7 d post-inoculation (dpi). Each dot represents bladder (closed symbols) and kidneys (open symbols) from an individual animal. Bars indicate the median CI. Significant differences in colonization (*P<0.05) were determined with the Wilcoxon signed-rank test. A CI<1 indicates a fitness defect. Growth of (C, E) E. coli CFT073 or (D, F) P. mirabilis HI4320 wild-type strains and mutants in: pgi, glucose-6-phosphate isomerase; pfkA, 6-phosphofructokinase transferase; tpiA, triosephosphate isomerase; and pykA, pyruvate kinase during culture in defined medium containing 0.2% glucose as the sole carbon source (C, D) or in LB medium (E, F). A representative growth curve is shown for each panel. Restoration of wild-type growth in triosephosphate isomerase mutants (G) growth in MOPS defined medium containing 0.2% glucose of E. coli CFT073 (pGEN), UPEC tpiA (pGEN), and the E. coli CFT073 tpiA mutant containing pGEN into which the tpiA gene from P. mirabilis was cloned. (H) P. mirabilis HI4320 containing empty vector (pGEN), HI4320 tpiA (pGEN), and complemented HI4320 tpiA mutant containing pGEN-tpiA in minimal salts medium containing 0.2% glucose. (I) In vivo complementation of P. mirabilis tpiA mutant bacteria. Competitive indices were determined following an in vivo co-challenge infection of female CBA/J mice with P. mirabilis HI4320 (pGEN) and HI4320 (tpiA pGEN-tpiA). Bacteria were recovered at 7 dpi. Each dot represents the CI in bladders (closed symbols) and kidneys (open symbols) from an individual animal. Bars represent the median CI. P-values are indicated on the graph.