Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New microscope technique could speed identification of deadly bacteria

08.06.2015

Holographic microscope coupled with machine-learning software, which could be an inexpensive, point-of-care solution for hospitals and contamination screening of food industries worldwide, will be tested in Tanzania next month

A new way of rapidly identifying bacteria, which requires a slight modification to a simple microscope, may change the way doctors approach treatment for patients who develop potentially deadly infections and may also help the food industry screen against contamination with harmful pathogens, according to researchers at the Korea Advanced Institute of Science and Technology (KAIST) in Daejeon, South Korea.


This image shows laser light bouncing off of individual bacteria under the microscope, creating holographic images of them, and then using a mathematical transformation and computer software to analyze the images and identify them by comparing them to other, known bacteria.

Credit: Young-Ju Jo and YongKeun (Paul) Park, Korea Advanced Institute of Science and Technology

Described this week in The Optical Society (OSA) journal, Optics Express, the new approach involves bouncing laser light off individual bacteria under the microscope, creating holographic images of them, and then using a mathematical transformation and computer software to analyze the images and identify them by comparing them to other, known bacteria.

The software uses a machine-learning algorithm -- the sort computers connected to security cameras might use for automated facial recognition.

If the approach proves to be effective in controlled clinical trials, it could lead to a powerful new way of routinely and almost immediately identifying dangerous bacteria at the bedside -- much faster than the days it normally takes to grow or "culture" the microbes in the laboratory from a patient's blood, which is still the gold standard in the health care industry for making a definitive diagnosis.

Also routinely used today is a newer method for rapidly identifying bacteria based on a DNA-analysis technique called quantitative polymerase chain reaction (qPCR), but it still may take hours to return a result, and it requires expensive sample preparation that is often cost prohibitive for routine use in rural or resource poor settings around the world.

The challenge of meeting clinical needs in the developing world was one of the motivations behind the work, according to the KAIST team. They wanted to find an inexpensive method that could surpass the speed of qPCR.

"Employing laser holographic techniques, we achieved rapid and label-free identification of bacterial species at the single bacterium level with a single-shot measurement," said physicist YongKeun Park, who led the KAIST team. "This means the present method can be utilized as a prescreening test for point-of-care bacterial diagnosis for various applications including medicine and food hygiene."

"We have also developed a compact portable device, so called quantitative phase imaging unit (QPIU) (Optics Letters 39 (12), 3630-3633), to convert an simple existing microscope to a holographic one, in order to measure light scattering patterns of individual bacteria, which can then be used to identify bacteria species for rural areas and developing countries," said Park. "Our team has plans to go to Tanzania next month for a field test."

Why Speed Matters in Infection Control

In hospitals and clinics worldwide, bacterial infections are a major source of illness, often slowing recovery or making matters much worse for people who are admitted to inpatient care for routine or emergency treatment. In the most severe cases, bacterial poisoning causes severe disease and syndromes like sepsis, meningitis, pneumonia, and gastroenteritis -- all of which can be deadly unless the patient is given immediate and appropriate treatment.

The true challenge of fighting those infections is time. In order to best treat their patients, doctors would like to know exactly which bacteria they are infected with, but the lost hours or days spent identifying the exact pathogen can make the road to recovery that much steeper. Sepsis, for instance, can develop so rapidly that mortality has been seen to increase by 9 percent per hour until treatment is given. Waiting two days may kill the patient, Park added.

For that reason, many hospital-acquired infections are treated presumptively, before they are definitively identified, using broad-spectrum antibiotics. These powerful combinations of potent drugs are often effective, but using them routinely raises the risk of deadly multidrug-resistant bacteria emerging.

The new QPIU technology promises to deliver better point-of-care diagnostics by reducing the time it takes to specifically identify bacteria, which may guide treatment, allowing doctors to prescribe the best drugs available to treat an infection and improving outcomes for people with hospital-acquired infections -- though the effectiveness of the approach remains to be proven in future clinical trials.

In their initial experiments, Park and his colleagues showed as a proof of principle that they could identify bacteria with high accuracy. They examined four different bacterial species (Listeria monocytogenes, Escherichia coli, Lactobacillus casei, and Bacillus subtilis). The first three are all pathogens known to infect humans through the food chain or via hospital-acquired infections. The fourth is a harmless bacteria used in laboratory research but of great interest because it is closely related to the deadly Bacillus anthracis, which is the base for Anthrax.

Under a microscope, all four of these rod-like bacteria look nearly identical. They would be virtually impossible to distinguish. The KAIST team, however, sorted them using the QPIU process with an accuracy greater than 94 percent.

The technique involves scattering light off the bacteria under the holographic microscope and then applying a mathematical function known as a Fourier Transform to the holographic images. The Fourier Transform allows them to define a distinct, fingerprint-like light scattering pattern for any given bacterial cell. They then applied software they designed to the analysis, which used a conventional approach to statistical classification known as machine learning -- a sorting strategy based on pattern similarities that has been extensively used in applications like facial recognition software. This was the first time anyone had applied machine learning to Fourier Transform light scattering data, Park said.

They are now looking to extend their initial work to see if they can distinguish between several types of bacterial subgroups -- to identify the most drug resistant or virulent strains from the innocuous ones.

In addition to helping in the clinic, the new method may be useful in the food industry or for homeland security applications. In principle, the approach could be scaled up to screen for contaminated food or suspicious packages.

###

About The Optical Society

Founded in 1916, The Optical Society (OSA) is the leading professional organization for scientists, engineers, students and entrepreneurs who fuel discoveries, shape real-life applications and accelerate achievements in the science of light. Through world-renowned publications, meetings and membership initiatives, OSA provides quality research, inspired interactions and dedicated resources for its extensive global network of optics and photonics experts. OSA is a founding partner of the National Photonics Initiative and the 2015 International Year of Light. For more information, visit http://www.osa.org.

Media Contacts:

Rebecca B. Andersen
The Optical Society
randersen@osa.org
+1 202.416.1443

Joshua Miller
The Optical Society
jmiller@osa.org
+1 202.416.1435

Research Contact:

YongKeun (Paul) Park
KAIST

yk.park@kaist.ac.kr

Rebecca Andersen | EurekAlert!

More articles from Physics and Astronomy:

nachricht Climate cycles may explain how running water carved Mars' surface features
02.12.2016 | Penn State

nachricht What do Netflix, Google and planetary systems have in common?
02.12.2016 | University of Toronto

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>