Distribution of genes encoding adhesins and biofilm formation capacity among Uropathogenic Escherichia coli isolates in relation to the antimicrobial resistance

Abstract

Background: Escherichia coli is the most predominant pathogen involved in UTIs. Mainly, fimbrial surface appendages are implicated in adherence to urothelium besides non-fimbrial proteins.

Objectives: to determine prevalence of genes encoding fimbrial and non-fimbrial proteins among Uropathogenic Escherichia coli (UPEC). Furthermore, distribution of these genes and biofilm formation capacity were investigated in relation to antimicrobial resistance.

Methods: Antimicrobial susceptibility of 112 UPEC isolates was performed using disc diffusion method. ESBL production was confirmed by double disc synergy test. Genes encoding fimbrial and non-fimbrial proteins were detected using PCR and biofilm formation was investigated using microtitre plate assay.

Results: UPEC isolates exhibited high resistance against doxycyclines (88.39 %), β-lactams (7.14-86.6%), sulphamethoxazole-trimethoprim (53.75%) and fluoro-quinolones (50%). Fifty percent of tested isolates were ESBL producers. PapGII gene was statistically more prevalent among pyelonephritis isolates. SfaS, focG and picU genes were statistically associated with fluoroquinolone (FQs) sensitive isolates and Dr/afaBC gene was statistically associated with ESBL production. Moreover, non-MDR isolates produced sturdier biofilm.

Conclusion: PapGII adhesin variant seems to have a critical role in colonization of upper urinary tract. There is a possible link between antimicrobial resistance and virulence being capable of affecting the distribution of some genes besides its negative impact on biofilm formation.

Keywords: ESBL; Escherichia coli; UPEC; Urinary tract infection; adhesin genes; biofilm.

Figure 1

Gel electrophoresis of genes encoding fimbrial adhesins : L1 and L7 represent 100bp DNA ladder, L2 represents papG_II allele band approximately at 190 bp, L3 represents papG_III allele band approximately at 258 bp, L4 represents focG gene approximately at 360 bp, L5 represents sfaS gene approximately at 240 bp and L6 represents Dr/afaBC gene band approximately at 559 bp.

Figure 2

Gel electrophoresis of genes encoding afimbrial proteins: L1 and L6 represent 100bp DNA ladder, L2 represents gene encoding Ag43 autotransport protein band approximately at 433 bp, L3 represents gene encoding secreted autotransprt protein picU band approximately at 572 bp, L4 gene encoding outer membrane protein Iha band approximately at 827 bp and L5 represents gene encoding outer membrane protein ompt band approximately at 559 bp.