Virulence genes in Escherichia coli strains isolated from urine of elderly patients

Urinary tract infections (UTIs) are one of the most frequent infections in elderly people. The majority of infections is caused by uropathogenic E. coli. These strains contain a broad spectrum of virulence factors and are able to overcome defense barriers and colonize host organism. Population of elderly individuals has been growing globally and for that reason it is possible to expect a rise of UTIs among them. The aim of this study was to determine the phylogenetic group (A, B1, B2 and D) of urinary strains of E. coli isolated from elderly patients and evaluate the presence of 14 virulence genes (hly, cnf1, cdt, sat, afa, sfa, pap, aer, upaH, cah, pic, neuC, kpsMT II and traT) in these strains. We have carried out a phylogenetic analysis and virulence genes identification of 75 urinary E. coli isolates. Among our 75 E. coli strains, phylogenetic group B2 (64%) was the most dominant followed by groups D (16%), B1 (10.7%) and A (9.3%). The genes kpsMT II (65.3%), traT (61.3%), upaH (58.6%) and aer (52.0%) were found to be the most prevalent. We identified from 5 to 10 virulence genes in 44% strains belonging to B2 phylogroup. E. coli urinary strains examined in this study belonged mainly to phylogenetic group B2. We have also found that the majority of examined virulence genes, which are crucial for the establishment and maintenance of infection, were present in these strains.