FIMBRIAE AND FLAGELLA MEDIATED SURFACE MOTILITY AND THE EFFECT OF GLUCOSE ON NONPATHOGENIC AND UROPATHOGENICESCHERICHIA COLI

Abstract

word count: 223 15 Text word count (including abstract and importance): 3965 16 17 2ABSTRACT 18 We characterized the surface motility of nonpathogenic and pathogenic E. coli strains 19 with respect to the appendage requirement, flagella versus fimbriae, and the glucose requirement. 20 Nonpathogenic lab strains exhibited either slow or fast surface movement. The slow strains 21 required type 1 fimbriae for movement, while the fast strains required flagella and had an 22 insertion in the flhDC promoter region. Surface movement of three uropathogenic E. coli 23 (UPEC) strains was fast and required flagella, but these strains did not have an insertion in the 24 flhDC promoter region. We assessed swimming motility as an indicator of flagella synthesis and 25 found that glucose inhibited swimming of the slow nonpathogenic strains but not of the fast 26 nonpathogenic or pathogenic strains. Fimbriae-based surface motility requires glucose, which 27 inhibits cyclic-AMP (cAMP) and flagella synthesis; therefore, we examined whether surface 28 motility required cAMP. The surface motility of a slow, fimbriae-dominant, nonpathogenic strain 29 did not require cAMP, which was expected because fimbriae synthesis does not require cAMP. 30In contrast, the surface motility of a faster, flagella-dominant, UPEC strain required cAMP, 31 which was unexpected because swarming was unaffected by the presence of glucose. Electron 32 microscopy verified the presence or absence of fimbriae or flagella. In summary, surface 33 motilities of the nonpathogenic and uropathogenic E. coli strains of this study differed in the 34 appendage used and the effects of glucose on flagella synthesis. 35 36 IMPORTANCE 37Uropathogenic Escherichia coli strains cause 80-90% of community-acquired urinary 38 tract infections, and recurrent urinary tract infections, which can last for years, and often become 39 antibiotic resistant. Urinary tract infections can be associated with intra-vesical lesions extending 40 3 from localized trigonitis/cystitis to widely distributed pancystitis: motility may be a factor that 41 distinguishes between these infection patterns. Nonpathogenic and uropathogenic E. coli were 42 shown to exhibit fimbriae-and flagella-dependent surface motility, respectively, and the 43 difference was attributed to altered control of flagella synthesis by glucose. Uropathogenic E. 44 coli strains grow more rapidly in urine than nonpathogenic strains, which implies differences in 45 metabolism. Understanding the basis for glucose-insensitive control of flagella-dependent 46 motility could provide insight into uropathogenic E. coli metabolism and virulence. 47 48 49 Escherichia coli is an extraordinarily successful pathogen which causes a variety of 50 diseases, including urinary tract infections (1). Uropathogenic E. coli (UPEC) is the predominant 51 cause of acute and recurrent urinary tract infections, which can become antibiotic resistant and 52 persist for years (2, 3). In women with recurrent urinary tract infections (rUTIs), the cla...

The Nutrient and Energy Pathway Requirements for Surface Motility of Nonpathogenic and Uropathogenic Escherichia coli

“…Swimming with glucose is unexpected, since glucose should prevent cyclic AMP synthesis which is required for flagella synthesis (30). However, we have shown that glucose does not prevent flagella synthesis in several pathogenic E. coli strains, which shows that the absence of a glucose effect is not strain dependent (11). UTI89 fliC, which lacks flagella, moved a little on the surface in the presence of glucose (Fig 8).…”

“…UTI89 fliC, which lacks flagella, moved a little on the surface in the presence of glucose (Fig 8). This surface movement required pili because UTI89 fliC fimA failed to move (11). In summary, glucose promotes surface movement in strains lacking flagella.…”

“…Cells from the edge of the plate were isolated and shown to move without any carbohydrate ( Fig 7C). A possible explanation for enhanced motility is an insertion in the promoter region of the flhDC operon (11,29). PCR analysis of this region showed no insertion upstream from the flhDC structural genes (not shown).…”

“…We examined the glucose requirement for surface motility for three strains: nonpathogenic W3110 which requires pili for surface movement; J1 which is a hypermotile derivative of W3110 that utilizes flagella for surface movement because of an IS5 insertion in the flhDC promoter region; and uropathogenic UTI89 which also moves with flagella (11).…”

“…The authors suggested that some genes for pili synthesis were required for flagella synthesis which is not consistent with subsequent evidence that pili and flagella synthesis are mutually exclusive (9-11). Our recent results show that surface motility of common E. coli lab strains, including the parental strain of the Keio mutants, requires pili, but fast variants rapidly appear due to a mutation that increases expression of the master regulator for flagella synthesis (11). In other words, results using Keio collection mutants involved strains that either expressed pili or flagella or both if a flagella-synthesizing variant was generated during the motility assay.…”