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HomeInfectious DiseasesRapid test to check antibiotic efficacy against urinary-tract bacteria

Rapid test to check antibiotic efficacy against urinary-tract bacteria

AstregoResearchers at Uppsala University have developed a new method for rapidly determining whether urinary tract infection-causing bacteria are resistant or susceptible to antibiotics.

Antibiotic resistance is a growing medical problem that threatens human health globally. One important contributory factor in the development of resistance is the incorrect use of antibiotics for treatment. Reliable methods to quickly and easily identify bacterial resistance patterns (Antibiotic Susceptibility Testing, AST) and provide the proper treatment from the start, (right from the doctor's appointment), are a solution to the problem. This has not been possible because existing antibiotic resistance tests take too long.

Now, researchers at Uppsala have, for the first time, developed an antibiotic resistance test that is fast enough to enable a patient to take the right antibiotic home from the health centre straight after the first appointment. The test is primarily intended for urinary tract infections – a condition that, globally, affects approximately 100m women a year and accounts for 25% of antibiotic use in Sweden.

"We've developed a new method that allows determination of bacterial resistance patterns in urinary tract infections in 10 to 30 minutes. By comparison, the resistance determination currently in use requires one to two days. The rapid test is based on a new plastic microfluidic chip where the bacteria are trapped and methods for analysing bacterial growth at single-cell level," says PhD student Özden Baltekin, who performed most of the experimental work.

The "fASTest" method is based on sensitive optical and analytical techniques developed to study the behaviour of individual bacteria. Monitoring whether individual bacteria grow in the presence of antibiotics (are resistant) or not (are susceptible) reveals their resistance or susceptibility within a few minutes.

"It's great that the research methods we developed to address fundamental questions in molecular biology can come in useful for such a tremendously important medical application," says Johan Elf, one of the researchers behind the study.

The detection method is now being developed by an Uppsala company, Astrego Diagnostics (AB), into a user-friendly product. The company expects to have an automated test for urinary tract infections within a few years.

"The hope is that, in future, the method could be used in hospitals and health centres to quickly provide correct treatment and reduce unnecessary use of antibiotics," says Dan Andersson, one of the researchers behind the study. "We believe the method is usable for other types of infection, such as blood infections where prompt, correct choice of antibiotic is critical to the patient."

Abstract
The emergence and spread of antibiotic-resistant bacteria are aggravated by incorrect prescription and use of antibiotics. A core problem is that there is no sufficiently fast diagnostic test to guide correct antibiotic prescription at the point of care. Here, we investigate if it is possible to develop a point-of-care susceptibility test for urinary tract infection, a disease that 100 million women suffer from annually and that exhibits widespread antibiotic resistance. We capture bacterial cells directly from samples with low bacterial counts (104 cfu/mL) using a custom-designed microfluidic chip and monitor their individual growth rates using microscopy. By averaging the growth rate response to an antibiotic over many individual cells, we can push the detection time to the biological response time of the bacteria. We find that it is possible to detect changes in growth rate in response to each of nine antibiotics that are used to treat urinary tract infections in minutes. In a test of 49 clinical uropathogenic Escherichia coli (UPEC) isolates, all were correctly classified as susceptible or resistant to ciprofloxacin in less than 10 min. The total time for antibiotic susceptibility testing, from loading of sample to diagnostic readout, is less than 30 min, which allows the development of a point-of-care test that can guide correct treatment of urinary tract infection.

Authors
Özden Baltekin, Alexis Boucharin, Eva Tano, Dan I. Andersson, Johan Elf

[link url="http://www.uu.se/en/media/news/article/?id=9114&area=2,4,10,16,24&typ=artikel&lang=en"]Uppsala University material[/link]
[link url="http://www.pnas.org/content/early/2017/08/07/1708558114"]Proceedings of the National Academy of Sciences abstract[/link]

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