Biofilm formation in uropathogenic Escherichia coli strains: relationship with prostatitis, urovirulence factors and antimicrobial resistance.
OBJECTIVE
Escherichia coli strains are the most frequent cause of urinary tract infections. Biofilm formation allows the strains to persist a long time in the genitourinary tract and interfere with bacterial eradication. We determined the possible relationships between the different urinary tract infections, and in vitro biofilm formation, the presence of urovirulence factors and nalidixic acid resistance.


METHODS
A total of 151 E. coli strains collected from patients with cystitis (44 strains), pyelonephritis (75) and prostatitis (32) were analyzed for in vitro biofilm formation, the phylogenetic group, the presence of several urovirulence factors and resistance to nalidixic acid.


RESULTS
E. coli strains causing prostatitis produced biofilm in vitro more frequently than those causing other urinary tract infections and had a higher frequency of hemolysin (p = 0.03 and 0.0002, respectively). However, only hemolysin was independently associated with prostatitis. On the other hand, strains forming biofilm presented a significantly higher frequency of hemolysin and type 1 fimbriae expression.


CONCLUSIONS
Although hemolysin is the main virulence factor by which E. coli causes acute prostatitis, the association between hemolysin and biofilm formation may result in increased ability of E. coli strains to persist in the prostate.
Soto
S M
SM
Microbiology and Infectious Diseases, Institut d'Investigacions Biomèdiques August Pi i Sunyer, School of Medicine, University of Barcelona, Barcelona, Spain.
Smithson
A
A
Martinez
J A
JA
Horcajada
J P
JP
Mensa
J
J
Vila
J
J
D018441:Biofilms; D003556:Cystitis / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000472:pathogenicity* / Q000502:physiology*; D004927:Escherichia coli Infections; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011472:Prostatitis / Q000382:microbiology*; D037521:Virulence Factors
D037521:Virulence Factors