Comparison of Tissue Culture Plate, Congo red Agar and Tube Methods for Evaluation of Biofilm Formation among Uropathogenic E. coli Isolates

Background and Aims: Microorganisms within biofilms,, formed on medical devices in the body are highly resistant to antimicrobial compounds and host responses and play a major role in nosocomial infections, especially urinary tract infections (UTIs). Uropathogenic Escherichia coli (UPEC) causes ۵۰% of the hospital-acquired urinary tract infections and is capable to form biofilm in the bladder epithelium which plays an important role in its pathogenesisThe identification of biofilm producing UPEC strains by routine laboratory methods is important for the better understanding of the pathogenesis of this bacterium in UTIs. Materials and Methods: A total of ۱۰۰ UPEC strains were collected from patients with UTIs in a hospital inTehran in ۲۰۱۶ and diagnosed by biochemical tests and the ability of biofilm formation was determined by Tissue Culture Plate (TCP), tube method (TM) and Congo red agar (CRA) methods. Sensitivity and specificity of methods were determined. Results: In tube method, ۲۳% of the isolates formed strong and ۵۹% formed weak biofilm. In Tissue Culture Plate method ۴۰%, ۲۲% and ۲۸% of isolates formed strong, moderate and weak biofilm respectively and ۱۰% were biofilm negative. According to the Congo red agar method only ۴% of the isolates formed strong biofilm, ۶۵% and ۳۱% respectively had a weak biofilm and no biofilm. The sensitivity and specificity of Congo red agar and Tube methods were ۳۹.۱%, ۵۰.۹% and their features were ۷۸.۳%, ۷۹.۷% respectively. Conclusions: The results showed that Tissue Culture Plate method is important for the determination of UPEC biofilm formation. Tube method and Congo red agar are not reliable methods for this purpose.

کلیدواژه ها:

Uropathogenic Escherichia coli ، Biofilm formation ، Phenotypic methods ، اشریشیا کلی یوروپاتوژن ، تشکیل بیوفیلم ، روش های فنوتیپی