New detection method for UTI-causing bacteria means better treatment and fewer costs

January 25, 2012
Bacteria are being deposited on a metal plate for analysis. Credit: Burkhard Buscher, University Hospital Essen

A new method for identifying bacteria that cause urinary tract infections (UTIs) will lead to much faster, more effective treatment as well as a reduction in costs. The procedure, described in the Journal of Medical Microbiology, could eventually be used for the identification of micro-organisms in other bodily fluids, including blood and spinal fluid.

Scientists at the University Hospital Essen in Germany tested from in-house patients and were able to effectively separate and accurately identify using a technique called Matrix-Assisted Laser Desorption Ionization-Time of Flight (MALDI-TOF) mass spectrometry.

Currently, bacteria from urine are identified by biochemical testing of the that are able to grow on agar plates. This standard method is not ideal; in the best case scenario, results are available after 12 hours, but longer are not uncommon. If the patient has already been treated with antibiotics, this can impair on agar which increases the probability of misclassification. If doctors are unable to precisely identify the bacterium causing the UTI, a broad spectrum antibiotic is prescribed. These are less effective than specifically targeted antibiotics and also encourage development of .

The MALDI-TOF technique identifies bacteria by analysing their proteins directly from the urine sample. MALDI-TOF mass spectrometry works by firing pulses of UV light at . All the particles become either positively or negatively charged and are then forced down a tunnel by an electrical force. As the particles have the same charge, their speed is dependent on their mass, allowing biomolecules such as proteins or DNA to be identified. As bacteria do not need to be cultured on agar, the MALDI-TOF method cuts the time to identify UTI-causing bacteria to less than 30 minutes. In addition, MALDI-TOF can detect and identify bacteria at much lower levels than are needed for current standard diagnostic techniques.

Dr Frank Mosel who led the study, believes the MALDI-TOF method will have huge benefits for patients that suffer from UTIs. "Identifying bacteria quickly and accurately using MALDI-TOF means treatment for UTIs can be started at an early stage and with an antibiotic targeted at the correct bacterial culprit. This should mean less patient suffering, fewer complications and a reduction in costs of both diagnosis and therapy," he stated. "What's more, the sensitivity of the test is nearly 100 times higher than the minimum clinical threshold for UTI diagnosis. This means that developing infections can be identified in routine urine samples before clinical symptoms appear. This is particularly helpful for catheterised hospital patients who may have weakened immune systems and be therefore more susceptible to infection," explained Dr Mosel.

The study revealed some limitations in the use of MALDI-TOF to identify bacteria causing UTIs. "Bacteria in urine samples from patients who had undergone surgery for lower urinary tract (e.g. bladder) cancers could not be detected. The human proteins produced interfere with the urine analysis, causing detection problems," said Hedda Köhling, the co-worker of Dr Mosel. "It is important to find out if there are other situations which compromise the effectiveness of the MALDI-TOF method," she said.

Dr Mosel believes that the use of MALDI-TOF mass spectrometry could be extended more widely as a medical analysis tool. "This method could quite feasibility be extended to blood, cerebrospinal fluid and other bodily fluids to detect bacteria or even fungi," he said. "One of the big advantages is that every sample can be processed independently without any prior assumptions about what microbes will be found," said Dr Mosel.

Explore further: Sensitive detection method analyzes circulating tumor cells in patients with lung cancer

Related Stories

Recommended for you

Flu study, on hold, yields new vaccine technology

September 2, 2015

Vaccines to protect against an avian influenza pandemic as well as seasonal flu may be mass produced more quickly and efficiently using technology described today by researchers at the University of Wisconsin-Madison in the ...

We've all got a blind spot, but it can be shrunk

August 31, 2015

You've probably never noticed, but the human eye includes an unavoidable blind spot. That's because the optic nerve that sends visual signals to the brain must pass through the retina, which creates a hole in that light-sensitive ...

Biologists identify mechanisms of embryonic wound repair

August 31, 2015

It's like something out of a science-fiction movie - time-lapse photography showing how wounds in embryos of fruit flies heal themselves. The images are not only real; they shed light on ways to improve wound recovery in ...

New 'Tissue Velcro' could help repair damaged hearts

August 28, 2015

Engineers at the University of Toronto just made assembling functional heart tissue as easy as fastening your shoes. The team has created a biocompatible scaffold that allows sheets of beating heart cells to snap together ...

Fertilization discovery: Do sperm wield tiny harpoons?

August 26, 2015

Could the sperm harpoon the egg to facilitate fertilization? That's the intriguing possibility raised by the University of Virginia School of Medicine's discovery that a protein within the head of the sperm forms spiky filaments, ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.