Antimicrobial resistance in relation to virulence determinants and phylogenetic background among uropathogenic Escherichia coli in Lebanon.

Escherichia coli is the most common causative agent of recurrent, uncomplicated urinary tract infections. Triplex pCR and the disc diffusion method were used to determine and correlate among the phylogenetic group, virulence determinants and antimicrobial resistance in 100 uropathogens. Group B2 represented 58% of the tested isolates with no isolates belonging to group B1. Isolates with the highest percentage of susceptibility to all antimicrobial agents used were within the B2 phylogenetic groups. 38% of the tested population were resistant to trimethoprim/sulfamethoxazole, 29% to ciprofloxacin and only 8% to nitrofurantoin. The majority of the isolates resistant to trimethoprim/sulfamethoxazole were from group B2 (52.7%), with 45% being positive to the three tested virulence determinants (efu, fbp and picU). These findings suggest that although virulence and antimicrobial resistance are mutually exclusive in Escherichia coli clinical isolates, the relationship between virulence and resistance to antimicrobial agents can vary according to the particular resistance phenotype.