Genetic adhesion profiles and adhesive variability of uropathogenic <i>Escherichia coli</i> strains

Abstract

Our study was aimed at investigating prevalence of adhesion genetic determinants among uropathogenic E. coli strains and assessing their correlation with level of specific and non-specific adhesion. E. coli bacterial cultures (n = 33) isolated from patients with urinary tract infection were examined. A phylogenetic group of strains was detected by using Clermont quadriplex-PCR method. Detection of fimbrial and afimbrial adhesin genes was carried out with end-point PCR. Level of erythrocyte-specific, non-specific hydrophobic and hydrophilic adhesion as well as biofilm formation were estimated by using standard methods. Adhesin genes were detected with the following frequencies: fimH — 75.76%, flu — 66.67%, iha — 39.40%, papC — 33.33%. Each of the genes sfaDE, upaG, afa/draBC and yqi was found with frequency 18.18%, whereas eaeA was not detected. Seven strains (21.21%) carried solely fimbrial adhesin genes, three strains (9.09%) — afimbrial adhesin genes, and twenty-one strains (63.64%) had genes of both adhesin types. Twenty-three individual adhesion genotypes were found among thirty-three UPEC strains. A combination of at least four genes were detected in 45.45% strains, among which 60% belonged to phylogroup B2. Odds ratio for adhesin gene prevalence in B2 group was calculated. It was shown that in B2 group yqi and sfaDE genes were detected by 14-fold more frequently (OR = 14.286) than in other phylogroups, and flu gene was observed at 10-fold higher rate (OR = 10.000). No correlation between such genes and level of adhesion to erythrocytes was found, whereas fimH+, papC+ and upaG+ strains had higher level of non-specific hydrophilic adhesion. It was shown that fimbrial adhesins accounted for bacterial adhesion and biofilm formation stronger than afimbrial ones. Thicker biofilm tended to form on latex catheter surface for strains with positive genetic profile for adhesin gene carriers.