Nutrient and energy pathway requirements for surface motility of nonpathogenic and uropathogenic escherichia coli

Uropathogenic Escherichia coli (UPEC) is the causative pathogen for most uncomplicated urinary tract infections (UTIs). Motility is likely to contribute to these infections, and E. coli possesses flagellum-dependent swimming motility, flagellum-dependent surface motility (often called swarming), and the recently observed pilus-dependent surface motility. Surface motility has not been extensively studied, but for the strains that have been tested, nonpathogenic E. coli (NPEC) laboratory strains use pili, NPEC hypermotile derivatives of these laboratory strains use flagella, and UPEC strains use flagella. Using a representative of these three types of strains, we showed differences in the nutritional and pathway requirements for surface motility with respect to the glucose concentration, the glycolytic pathway utilized, acetogenesis, the tricarboxylic acid (TCA) cycle. In addition, glucose-controlled flagellum synthesis was shown for the NPEC strain but not for the hypermotile NPEC variant or the UPEC strain. The requirements for surface motility are likely to reflect major metabolic differences between strains for the pathways and regulation of energy metabolism. IMPORTANCE Urinary tract infections (UTIs) are one of the most common bacterial infections and are an increasing burden on the health care system because of recurrence and antibiotic resistance (1, 2). The most common uropathogen is E. coli (3, 4), which is responsible for about 80 to 90% of community-acquired UTIs and 40 to 50% of nosocomially acquired UTIs (2). Virulence requires both pili and flagella, and either appendage can contribute to surface motility, although the surface motility of uropathogenic E. coli has not been examined. We found different appendage, nutrient, and pathway requirements for the surface motility of a nonpathogenic E. coli laboratory strain and a uropathogenic E. coli strain. We propose that these differences are the result of differences in the pathways and regulation of energy metabolism.