The current laboratory practice for the diagnosis of urinary tract infections is growing culture specimens of the contaminating pathogens from urine specimens until they can be visually identified on the culture plates. While this century-old technique has worked very well, the major drawback is the two-day time lag between specimen collection and bacteria identification. Hence, physicians must decide whether to prescribe antibiotic therapy and, if so, which type of bacteria to treat -- all without knowing the cause of the infection, if any.

Fortunately, a promising new biosensor technology has been developed that may replace this antiquated testing methods and save precious health care dollars. The research, reported in the February 2006 issue of the peer-reviewed Journal of Clinical Microbiology, investigated a new technology to solve an old problem: the diagnosis of urinary tract infections -- the second most common bacterial infection -- in a clinically relevant timeframe.

In a recent clinical study conducted by the David Geffen School of Medicine at UCLA and the Veterans Affairs Greater Los Angeles Healthcare System, researchers used a biosensor developed by corporate partner GeneFluidics to identify correctly the infection-causing gram negative bacteria species in 98 percent of the tested clinical urinary tract infection urine samples. These results represent the first ever species-specific detection of bacteria in human clinical fluid samples using a microfabricated electrochemical sensor array.

Individual sensors on GeneFluidics' 16-sensor chips were coated with UCLA-designed species-specific genetic probes. Clinical urine samples were directly applied to the chips and the electrochemical signal subsequently measured by GeneFluidics' multi-channel reader instrument. The urinary tract infection pathogens were identified by examining which signals on the sensor chip were elevated. The entire experiment from sample collection to result read-out took only 45 minutes.

Urinary tract infection is the most common urological disease in the United States and the most common bacterial infection of any organ system. On-going studies are focused on developing even better detection methods to bring the urinary tract infection biosensor chip from "bench to bedside." The team anticipates the rapid test could become available in the next two to three years and promises that a time will come when laboratory-quality testing can be rapidly performed by anyone, anywhere, and the results made available in real-time.

Sources: [EurekAlert] and [Medical News Today]

Photo Source: [UCLA Newsroom]