Urinary tract infection (UTI) is a symptomatic bacterial infection that occurs within the urinary tract and is one of the most prevailing infectious diseases with a substantial financial burden on society. It is indeed estimated that 15% of all community-prescribed antibiotics in some EU countries are dispensed for UTI1. With the alarming state of microbial resistance development, it is vital to develop fast point of care tools to detect UTI as well as to record its resistance to medical treatments. Yet, the diagnosis of UTI by specialists/doctors in hospitals or clinics is not an easy task due to the small timeframe of visits, thus there is an urgent need of point-of-care devices that give fast and reliable diagnosis within a comfortable waiting time (<30 mins).
Urine dip stick test is the basic and most frequently used method for UTI diagnostic testing. Such tests can detect nitrite, pH, leukocyte esterase, protein, glucose, etc. The result is constant, however, urine dip sticks suffer from a relatively low sensitivity and specificity. Only if elevated leukocyte esterase that points to the presence of white blood cells is tested, further bacteriological urine culture, which is the gold standard for a UTI test, will be performed to identify the specific pathogens under microscopy. Despite its acceptance, this technique is still suffering from various shortcomings: it is laborious, time-consuming and expensive since it requires specialized laboratory facilities to perform each test.
To overcome the shortcomings of existing diagnosis tools, this project aims at developing a new diagnosis tool using genetic identification based on quantitative polymerase chain reaction (qPCR) methods for UTI diagnosis. qPCR is a rapid method for quantification of nucleic acid sequences that combines PCR chemistry with fluorescent probe detection of amplified DNA segments. For point-of-care applications, miniaturization of PCR devices leads to faster DNA amplification process and lower costs of the biological sample consumption. Several integrated microfluidic nucleic acid testing devices have been reported, however, to facilitate tests at the point of care, it is ideal to integrate biosample preparation with the PCR reactions and fluorescence analysis into a single platform. For UTI diagnostics, it means that DNA of the infectious bacteria (e.g. Escherichia coli) need to be purified from patient urine and specific gene target is investigated afterwards. Such reported point-of-care diagnostic devices are rare because of the following challenges: (i) to perform cell concentration and lysis full-automatically; (ii) to integrate sample preparation and analysis into a single system; (iii) to miniaturize the plug-and-play operating system; (iv) to reduce the cost of the disposable chip.
This project is based on BforCure proprietary FASTGENE technology, the world fastest qPCR technique which has already been tested on Anthrax and Ebola simulating agents. Within this project, a fully automatic lab-on-a-chip cell concentration system has been developed first. Then we validated the workflow from our developed cell-concentration system to PCR analysis. This automatic system has been interested by a couple of industrial partners and we successfully did a proof-of-concept demo to them, such as legionella detection in big volume (1L) tap water. At the meantime, we developed a prototype integrating urine sample preparation and qPCR for bacteria gene recognition for point-of-care UTI diagnostics. The prototype is aimed to perform bacteria filtration, lysis, PCR reagents mixing and PCR full-automatically within 30 minutes. It is also can be extended to many other applications, such as defense and security, water treatment, food safety monitoring, etc.
1 Guidelines on urological infections, European Association of Urology, 2015
