New test could show antibiotic resistance in ‘less than 45 minutes’
Image credit: Artinun Prekmoung | Dreamstime.com
Scientists in Scotland have developed a diagnostic test that aims to show the susceptibility of bacteria to antibiotics within 45 minutes.
The University of Strathclyde team demonstrated the low-cost, rapid diagnostic system in a research paper published in the journal Biosensors and Bioelectronics.
Under the NHS, laboratory testing of samples can take up to two days and the new test aims to allow doctors to be able to prescribe the correct antibiotic to a patient for an infection more quickly.
To prove the system could prescribe the correct antibiotic to a patient, the scientists examined the difference in growth profiles between staphylococcus aureus and MRSA. While the former is a common hospital-acquired bacterial infection sensitive to antibiotics, MRSA can be harder to treat.
As part of the study, both strains of bacteria were placed on electrodes covered in a special hydrogel deposit that monitored bacterial growth and also contained antibiotics.
Results showed that the susceptible strain can grow on electrodes modified with a gel containing no antibiotics but not when the sensor was seeded with an antibiotic.
However, due to its antibiotic resistance, the MRSA strain was still able to grow on electrodes that contained clinically relevant concentrations of antibiotics.
“There is a small difference between what makes an organism susceptible to an antibiotic and what makes it resistant,” said lead author Dr Stuart Hannah.
“In real terms, we were able to distinguish between the two strains in less than 45 minutes, which is a significant improvement on the current gold standard of up to two days.”
According to Hannah, the technology uses a low cost, commercially available sensor which acts like a mini culture dish that can deal with any type of clinical sample.
“The system is modified with a special gel deposit so that we can identify the difference between susceptible and resistant forms of common bacteria,” he added.
“Rapid result detection means you could pinpoint bacterial versus viral infections straight away and would be able to start working on the correct treatment more quickly for patients, which is very important for particular infections.
“Antibiotic resistance is less likely to develop if you give a narrower spectrum antibiotic.”
Antimicrobial resistance (AMR) - the ability of microorganisms like bacteria and fungi to grow in the presence of common antibiotics - has become an increasing problem.
According to a report released earlier this year by the United Nations and global health agencies, it could result in 10 million deaths worldwide each year by 2050 and damage to the economy as ‘catastrophic’ as the 2008-2009 global financial crisis.
The National Institute for Health and Care Excellence says AMR poses a ‘significant threat’ to public health.
To tackle this issue effectively, better diagnostic testing and new technologies that can speedily assess the effectiveness of antibiotics and which one to prescribe, are needed.
The team hopes the test could be used by pharmacists and other points of care, as well as being developed for commercial use. Furthermore, Dr Hannah suggested all the materials used “can be mass-manufactured, which means that it is cheap to produce a working test”.
He added that with the right commercial backing, a future device could be used at a local GP surgery, “they could effectively take a blood sample and do the test and have results within the hour, rather than sending samples to a laboratory and have to wait for a positive result,” he said.
“It could also have a place on intensive care wards,” he continued. “The first time someone is ill they are quite rightly given a broad-spectrum antibiotic and also they have to wait for 12-72 hours for a result from the hospital laboratory.
“We would hope that the test can be located at the bedside and that it will allow doctors to switch from a broad spectrum agent to the right drug quite quickly.”
The consultant anesthetist on the project, Dr David Alcorn from the Royal Alexandra Hospital in Paisley, said: “Being able to quickly diagnose infection is a great enough ability but to be able to also detect AMR (antimicrobial resistance) within such a short period of time could prove to be a wonderful tool.
“It means that vital diagnostic information could be provided for clinicians across intensive care units, operating theatres, and emergency departments, to enable them to give the right drug at the right time.
“There is also scope for this to have an enormous impact on general practice and day-to-day healthcare.”
Sign up to the E&T News e-mail to get great stories like this delivered to your inbox every day.