Environmental phosphate differentially affects virulence phenotypes of uropathogenic Escherichia coli isolates causative of prostatitis

GRILLO-PUERTAS, M.; MARTÍNEZ-ZAMORA, G.; RINTOUL, M. R.; SOTO, S. M.; RAPISARDA, V. A.

Virulence

Taylor & Francis Group

Año: 2015 vol. 6 p. 620 - 629

2150-5594

K-12 Escherichia coli cells grown in static media containing a critical phosphate (Pi) concentration ³25mM maintained a high polyphosphate (polyP) level in stationary phase, impairing biofilm formation, a phenomenon that is triggered by polyP degradation. Pi concentration in human urine is fluctuated according to health state. Here, the influence of environmental Pi concentration on the occurrence of virulence traits in uropathogenic E. coli (UPEC) isolated from acute prostatitis patients was evaluated. After a first screening, three isolates were selected according to differential biofilm formation profiles depending on media Pi concentration. For each, biofilm positive and negative conditions were established. Regardless of the isolate, biofilm formation capacity was accompanied with curli and cellulose production, swimming motility and expression of some key virulence factors associated with adhesion. When the selected isolates were grown in their non-biofilm-forming condition, low concentrations of nalidixic acid and ciprofloxacin induced biofilm formation. Interestingly, similar to laboratory strains, polyP degradation induced biofilm formation in the selected isolates. Results sustains the complexity of pathogenic E. coli in response to environmental Pi and the importance of polyP metabolism as an aspect involved in biofilm formation in both clinical isolates and laboratory strains.