Fast method to determine antibiotic effectiveness

Australian researchers have developed a new method that can both detect the presence of a bacterial infection and determine which antibiotics will be most effective for treatment in less than five hours, as opposed to days. Their research has been published in the journal eBioMedicine.

Without effective antibiotics, patients with bacterial infections deteriorate rapidly and can die within hours. However, the standard process to identify the bacteria causing an infection and match it with the best antibiotic treatment can take days. Researchers from the Harry Perkins Institute of Medical Research, The University of Western Australia (UWA) and PathWest Laboratory Medicine WA have now developed a faster, more effective process to confirm infections and find the most effective treatment for them.

“The established method involves growing bacteria from a patient sample, then applying different antibiotics to see which are effective,” said UWA Forrest Prospect Fellow Dr Kieran Mulroney. “Patients with serious infections cannot wait the several days it can take to return antibiotic test results. Consequently, the patient’s doctor has to rely on a best guess, ‘one size fits all’ antibiotic choice to treat patients.

“The biggest problem with prescribing broad-spectrum antibiotics is that it encourages some bacteria to become resistant to the antibiotics. This is a growing and serious problem worldwide, because antibiotic-resistant bacteria can spread from person to person and reduce treatment options.”

Quicker, more accurate tests mean treatment can be targeted to each infection, so the antibiotics are just right — not too strong and not ineffective. With this in mind, Mulroney and his team developed their two-step process.

“First, we developed a test to confirm if the cause of the patient’s serious illness is a bacterial infection. This test takes 30 minutes, rather than 1–2 days,” Mulroney said.

“Once a patient has a confirmed bacterial infection, we then expose the bacteria to different types of antibiotics in the laboratory. Using a device that measures hundreds of thousands of individual bacteria in just a few seconds, the research team can detect the damage antibiotics cause to bacteria, and then use this information to confirm which antibiotic will be an effective treatment. We can predict which antibiotics will be effective to treat that infection with 96.9% accuracy.”

WA Country Health Service Translation Fellow Dr Tim Inglis has seen the method develop from its earliest test tube observations into a robust clinical laboratory method with a broad range of applications, and said the time and effort it takes to produce accurate antibiotic test results make the technique very attractive to busy clinical laboratories.

“Even in the most advanced health systems, hospital patients risk bacterial infection through trauma wounds, surgery sites, breathing machines and indwelling catheters,” Inglis said. “This can lead to pneumonia, urinary tract, abdominal and bloodstream infections. Applying the research team’s new technology to these infections is expected to transform how quickly and effectively we treat patients in Western Australia and further afield.”

Image credit: ©stock.adobe.com/au/naihoet

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