Detection of Biofilm Among Uropathogenic Escherichia Coli Clinical Isolates in Suez Canal University Hospitals

Primary outcomes

1. antibiotic resistance

   Time frame: from 18-24 hours

   Susceptibility testing will be performed according to the standard Kirby-Bauer disk diffusion method on Mueller Hinton agar and interpreted according to the Clinical and Laboratory Standard Institute (CLSI) guidelines. Antibiotic discs include Amoxicillin-clavulanate, Piperacillin-tazobactam, Cefotaxime, Ceftazidime, Aztreonam, Imipenem, Gentamicin, Amikacin, Norfloxacin, ciprofloxacin, levofloxacin, Trimethoprim-sulfamethoxazole, Nitrofurantoin.

2. Congo red Agar method (CRA)

   Time frame: 24 to 48 hours

   The medium will be prepared by adding 37 gm brain heart infusion (BHI) powder, 50 gm sucrose and 10 gm agar to 900 ml distilled water and autoclaved at 121°C for 15 minutes. Congo red will be prepared separately by dissolving 0.8 gm of congo red stain in 100 ml distilled water as concentrated aqueous solution and autoclaved at 121°C for 15 minutes and thenit will be added to the previous media when it cooled to 55°C. The congo red agar will be distributed in sterile plates. Plates will be inoculated by the test bacteria and incubated aerobically for 24 to 48 hours at 37°C. Positive results will be indicated by black colonies with a dry crystalline consistency. Weak slime producers usually remain pink.

3. Modified tissue culture plate method (MTCP)

   Time frame: up to 24 hours

   All isolates will be screened for their ability to form biofilm by the TCP method with a modification in duration of incubation, which will be extended to 24 hours and the addition of glucose.