Urinary tract infections (UTIs) are a very common infection that affects 40% of women in their lifetimes (Bono, et al., 2023). UTIs are much less common in males due to biological differences in the urinary system, but they are still a relevant issue. The male urethra is roughly 5 times longer than the female, which reduces the risk of bacteria entering the urinary tract (Czajkowski, et al., 2021). Upwards of 75% of UTIs are caused by the bacteria Escherichia coli but can be caused by other bacteria, fungi, and viruses (Zagaglia, et al., 2022; Bono, et al., 2023). Most existing systems of UTI detection require purification or enrichment of the urine and the addition of many reagents, requiring days to get results (Pandey, et al., 2022). Thus, rapid and effective UTI detection is needed in clinical settings to improve diagnoses and treatment (Pandey et al., 2022).
Pandey et al. (2022) have developed a new method of UTI detection that works approximately an hour after the urine sample is taken and requires no purification. The authors use magnetic microgel beads (mMB) with grafted DNAzymes to produce a voltage signal in an electrochemical chip (e-chip) upon detection of E. coli. The microgel beads are created using a polymer called poly(oligo(ethylene glycol)) methacrylate, also known as POEGMA (Pandey et al., 2022). The authors use the carboxylic acid groups from the methacrylic acid residues on POEGMA and graft a specific DNAzyme using carbodiimide chemistry. DNAzymes are a special type of DNA that can be programmed to identify a specific sequence and cause the cleavage of DNA using Watson-Crick base pairing (Thomas, et al., 2021). Pandey et al. (2022) programmed the DNAzyme to recognize specific sites in E. coli DNA and cause the cleavage of its DNA barcode, a specific DNA sequence in organisms that identifies their species, and release it into the solution. Once this is completed, the beads are magnetically separated into a pellet, and the supernatant (with free-floating E. coli barcodes) is put on the e-chip. The DNA barcodes hybridize with specific probes on the e-chip to generate a change of current that can be detected. This process is seen in Figure 1 below.
After validation using E. coli spiked buffers, Pandey et al. (2022) wanted to test their system with real UTI-infected urine. The authors tested three different types of urine samples. The first was a coli+/clinical+ which has clinically significant levels of E. coli. The second had coli-/clinical+, which had clinically significant levels of Escherichia faecalis but no significant levels of E. coli. The third was coli-/clinical- which had no significant level of any bacteria. They were able to observe a current change for the coli+/clinical+ condition and the coli-/clinical+ condition, but no significant increase for the coli-/clinical- condition. The results from this are shown in Figure 2 below. These results prove that this method is a quick and effective way of detecting UTIs in patients.
Overall, the authors of this paper were able to identify a brand new effective detection system for UTIs in a clinical setting. Implementation of this system could significantly reduce detection time and increase the efficacy of treatments for UTIs. This system could be manipulated to detect a wide variety of bacteria and infections.
Works Cited
Bono, M.J., Leslie, S.W. and Reygaert, W.C., 2023. Urinary Tract Infection. In: StatPearls. [online] Treasure Island (FL): StatPearls Publishing. Available at: <http://www.ncbi.nlm.nih.gov/books/NBK470195/> [Accessed 30 March 2023].
Czajkowski, K., Broś-Konopielko, M. and Teliga-Czajkowska, J., 2021. Urinary tract infection in women. Przegla̜d Menopauzalny = Menopause Review, 20(1), pp.40–47. https://doi.org/10.5114/pm.2021.105382.
Pandey, R., Lu, Y., Osman, E., Saxena, S., Zhang, Z., Qian, S., Pollinzi, A., Smieja, M., Li, Y., Soleymani, L. and Hoare, T., 2022. DNAzyme-immobilizing microgel magnetic beads enable rapid, specific, culture-free, and wash-free electrochemical quantification of bacteria in untreated urine. ACS Sensors, 7(4), pp.985–994. https://doi.org/10.1021/acssensors.1c02440.
Thomas, I.B.K., Gaminda, K. a. P., Jayasinghe, C.D., Abeysinghe, D.T. and Senthilnithy, R., 2021. DNAzymes, novel therapeutic agents in cancer therapy: A review of concepts to applications. Journal of Nucleic Acids, 2021, p.e9365081. https://doi.org/10.1155/2021/9365081.
Zagaglia, C., Ammendolia, M.G., Maurizi, L., Nicoletti, M. and Longhi, C., 2022. Urinary tract infections caused by uropathogenic Escherichia coli strains—New strategies for an old pathogen. Microorganisms, 10(7), p.1425. https://doi.org/10.3390/microorganisms10071425.