complex interplay between type 1 fimbrial expression and flagellum-mediated motility of uropathogenic Escherichia coli.
Type 1 fimbriae and flagella have been previously shown to contribute to the virulence of uropathogenic Escherichia coli (UPEC) within the urinary tract. In this study, the relationship between motility and type 1 fimbrial expression was tested for UPEC strain CFT073 by examining the phenotypic effect of fimbrial expression on motility and the effect that induction of motility has on type 1 fimbrial expression. While constitutive expression of type 1 fimbriae resulted in a significant decrease in motility and flagellin expression (P < 0.0001), a loss of type 1 fimbrial expression did not result in increased motility. Additionally, hypermotility and flagellar gene over- and underexpression were not observed to affect the expression of type 1 fimbriae. Hence, it appeared that the relationship between type 1 fimbrial expression and motility is unidirectional, where the overexpression of type 1 fimbriae dramatically affects motility and flagellum expression but not vice versa. Moreover, the constitutive expression of type 1 fimbriae in UPEC cystitis isolate F11 and the laboratory strain E. coli K-12 MG1655 also resulted in decreased motility, suggesting that this phenomenon is not specific to CFT073 or UPEC in general. Lastly, by analyzing the repression of motility caused by constitutive type 1 fimbrial expression, it was concluded that the synthesis and presence of type 1 fimbriae at the bacterial surface is only partially responsible for the repression of motility, as evidenced by the partial restoration of motility in the CFT073 fim L-ON DeltafimAICDFGH mutant. Altogether, these data provide further insight into the complex interplay between type 1 fimbrial expression and flagellum-mediated motility.
Lane
M Chelsea
MC
Department of Microbiology and Immunology, University of Michigan Medical School, 5641 Medical Science Building II, 1150 West Medical Center Drive, Ann Arbor, MI 48109, USA.
Simms
Amy N
AN
Mobley
Harry L T
HL
D001224:Aspartic Acid / Q000378:metabolism; D002633:Chemotaxis; D004926:Escherichia coli / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D036781:Fimbriae Proteins / Q000096:biosynthesis*; D010861:Fimbriae, Bacterial / Q000235:genetics* / Q000648:ultrastructure; D005407:Flagella / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D008124:Locomotion; D046529:Microscopy, Electron, Transmission; D009876:Operon
D036781:Fimbriae Proteins; D001224:Aspartic Acid