Urinary tract infection: detection of Escherichia coli antigens in human urine with an ELIEDA immunoenzymatic assay

Abstract

Escherichia coli is the most common causative agent of urinary tract infection (UTI), and diagnosing this infection usually relies on bacteriologic methods. Nevertheless, screening methods can be useful for a rapid presumptive diagnosis even though some of these screening methods have low sensitivity or are expensive. To investigate a possible new alternative approach, an antigen-based immunoassay--enzyme-linked immunoelectrodiffusion assay (ELIEDA)--was standardized for screening for this bacterial infection. Combining counter-immunoelectrophoresis with an immunoenzymatic assay, the ELIEDA requires concentrated urine specimens, a cellulose acetate membrane, polyclonal antibodies to E. coli raised in rabbits, and peroxidase-labeled sheep antibodies to rabbit immunoglobulin G (IgG). This ELIEDA technique was evaluated using 244 urine specimens, 76 of them with E. coli, 47 with heterologous bacteria, and 121 without bacteria. In comparison to bacteriologic methods, the sensitivity, specificity, and positive and negative predictive values for the ELIEDA were 93.4%, 98.2%, 95.9%, and 97.1%, respectively. The data obtained suggest that this assay is useful for routine diagnostic screening for UTI caused by E. coli. In addition, since the ELIEDA stained membranes can be stored, this assay makes retrospective studies possible.

Thromboresistant/anti-biofilm catheters via electrochemically modulated nitric oxide release

“…Since E. coli is the cause of 80% of urinary tract infections (UTIs) in humans [38] and can easily adhere onto abiotic surfaces and mediate strong biofilm growth [39–40] , this bacterium was chosen to assess whether the catheters that are only turned “on” to generate NO at the end of the biofilm maturation process, can still abate cell viability significantly. Remarkably, as shown in Fig.…”

Market-ready U-AST kit: simple, fast, cost-effective solution for concurrently detecting urinary tract infection and antibiotic resistance

“…Some other techniques for detecting urinary tract infections include an antigen-based immunoassay called the enzyme-linked immunoelectrodiffusion assay (ELIEDA); however, it is a little more sophisticated because it requires expert handling and only identies E. coli and requires antibodies. 37 Recently, a hybrid method for urinary tract infection detection has also been introduced that can aid in the prediction of UTIs. 33 Another kind of UTI detection technique is metagenomic sequencing, although this requires specialized personnel and can be expensive.…”

Magnetic Bacteriophage‐Engineered Janus Micromotors for Selective Bacteria Capture and Detection

“…The limit of detection (1.0 × 10 5 CFU mL −1 ) is higher than that reported using Janus fiber rods micromotors for fluorescence detection of E. coli (from 10 2 to 10 5 CFU mL −1 ), [ 13 ] bacteriophage T4‐modified magnetic‐fluorescent microparticles coupled with flow cytometry (10 4 CFU mL −1 ) [ 26 ] or AuNPs and thiolated bacteriophages (10 2 CFU mL −1 ). [ 27 ] Yet, our limit of detection meets the level requirements of bacteria established as the cut‐off for the diagnosis of Urinary Tract Infections (UTIs, 10 5 CFU mL −1 ) [ 28 ] in less than 3 h and in microvolumes samples, holding thus considerable promise for further practical use.…”