Abstract:

Objective(s): Catheters are one of the factors for complicated urinary tract infections. Uropathogenic bacteria can attach to the catheter via cell surface hydrophobicity (CSH), form biofilms, and remain in urinary tract. The study was evaluated phenotypic and genotypic characteristics of fimbriae in Klebsiella pneumoniae and uropathogenic Escherichia coli (UPEC) isolates from patients with catheter-associated urinary tract infections (CAUTIs) and their association with biofilm formation. Materials and Methods: Urine specimens were collected through catheters in patients with CAUTIs. Sixty bacterial isolates were identified by biochemical tests. For determination of biofilm formation a tissue culture plate was used. Microbial adhesion to hydrocarbons (MATH) was conducted for CSH determination. The mannose-sensitive haemagglutination (MSHA) and mannose-resistant haemagglutination (MRHA) were determined for type 1 and type 3 fimbriae. Finally, the presence of genes encoding fimbriae was determined by PCR.Results: All isolates showed strong CSH, biofilm capacity and MRHA phenotype. The results showed that 20% of UPEC and 23% of K. pneumoniae isolates contained MSHA phenotypes. There was a significant association between biofilm formation and MSHA phenotype in UPEC isolates. The frequency of fimA (80%) and fimH (96.6%) in K. pneumoniae isolates was higher than UPEC isolates. Both types of bacterial isolates with MSHA phenotypes harbored the fimH gene. Conclusion: The phenotypic and genotypic characteristics of two bacterial species were highly similar. Also, the type of fimbriae affected bacterial biofilm formation through catheterization. It seems that fimH and mrk gene cluster subunits are suitable markers for identifying bacterial pathogenesis.

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