Researchers Use Electrical Signalling to Detect Bacteria

Researchers at the University of Warwick have found bacteria can be detected in minutes by zapping them with electricity.

Scientists at the university in the United Kingdom discovered healthy bacteria cells and those inhibited by antibiotics or UV light show different electric reactions. When zapped with an electrical field, live bacteria absorb dye molecules causing the cells to light up so they can be counted. Bacillus subtilis and E. coli were used as model organisms.

Testing commercial products for bacterial contamination can take days. During this time, they can cause significant numbers of illnesses and infections can become life threatening if not identified and treated appropriately.

The researchers’ findings, published in Proceedings of the National Academy of Sciences of the United States of America, could lead to development of medical devices that can rapidly detect live bacterial cells, evaluate the effects of antibiotics on growing bacteria colonies, or identify different types of bacteria and reveal antibiotic-resistant bacteria. One target is quality control in the water, pharmaceutical, food, and beverage industries.

James Stratford, from the School of Life Sciences and spinout company Cytecom, said “the system we have created can produce results which are similar to the plate counts used in medical and industrial testing but about 20 times faster. This could save many people’s lives and also benefit the economy by detecting contamination in manufacturing processes.”

Scientists showed bioelectrical signals from bacteria can be used to determine if they are alive or dead. The approach uses membrane-potential dynamics and electrical stimulation to differentiate between incapacitated and viable cells.

The team developed an experimental tool to study the relation of bacterial electrical signaling. Using it combined with time-lapse microscopy, they showed live and inhibited cells respond to electrical stimulation in opposite directions. A 2.5-second electrical stimulation caused hyperpolarization in unperturbed cells while inducing depolarization in inhibited cells.

Findings offer an approach for rapid detection of proliferative bacteria without observation of actual proliferation or time-consuming calibrations for bacterial species. It can detect proliferative cells within a minute after electrical stimulation.

Researchers founded a start-up company called Cytecom. The firm has been awarded a grant from Innovate UK, a national funding agency, which means devices could be available to researchers and businesses shortly.

The team combined biological experiments, engineering and mathematical modelling.

“This work demonstrates that bacterial electricity can lead to societally important technology, while at the same time gaining fundamental insights into our basic understanding of cells. The tool we developed can offer more opportunities by allowing experiments which were not possible to perform before,” said Munehiro Asally, assistant professor at the University of Warwick.

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NC State Developing New Technology that will Help Farmers Detect Plant Pathogens

The fresh food in your grocery stores could eventually get cheaper thanks in part to new technology being developed at NC State that’ll help farmers protect their crops better and apply just the right amount of chemicals to prevent disease.

When a crop gets diseased, it can spread really quickly in a field, so it’s essential for farmers to detect problems fast.

But, traditional methods of disease detection can take weeks. Now a team of NC State researchers have come up with something that’s much quicker and portable.

The device literally smells disease.

Currently, it’s being tested in a lab run by assistant professor Qingshan Wei of the Emerging Plant Disease & Global Food Security Cluster at NC State.

They’ve detailed their results in a paper published by the Journal Nature.

Here’s how it works in laymen’s terms.

When a plant is diseased, it will actually give off gasses.

To test their proof of concept, Wei’s team puts part of a tomato plant leaf in a sealed glass tube.

The wait about 15 minutes as the air in the sealed vial becomes saturated with volatiles from the plant.

Once enough gas is collected, a device attached to the back of a cell phone is used to suck the air from the vial into a chamber where it’s analyzed.

The gas reacts with a tiny paper strip that’s coated with chemical dots.

The dots change color based on the disease affecting the plant.

The cell phone user then takes a magnified picture of the strip to be used by them as a reference on what chemical treatments need to be applied to the crops to stop the spread of disease.

“You want to know if it’s a bacterial infection or a fungal infection or other type of infection and guide your treatment steps,” said Wei.

Right now, the sniffer device only works on potato leaves and tomato leaves, but Wei’s team is developing sensors which will work with other crops.

The idea for the sensor was built on previous discoveries by other researchers who found out diseased plants gave off certain gasses.

“The leaf is breathing,” said Wei. “It’s exchanging molecules with the air.”

Right now, a farmers only options for figuring out what’s plaguing a crop is either guesswork or sending a sample to as clinical lab where it can take weeks to figure out the pathogen affecting the plants.

By the time the results are sent back to the farmer, the disease could have ruined an entire field of crops.

Once this lab porotype is fully developed, farmers will be able to use it in their fields to get instant results and can minimize the amount of chemical they apply.

“You want to have a rapid decision if you want to apply a fungicide or not,” said Wei.

Deciding how much and what chemical to apply is important because the less that’s applied is better for the environment.

And, saving a crop early will end up keeping prices lower because farmers won’t lose as much in the field.

Actual use of the sniffer is still about a year or so away because as it still needs a little more testing.

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Mesa Biotech to Present Comparative Flu & RSV Detection Analysis with Other FDA-Cleared Molecular Assays at AACC

Mesa Biotech Inc. is a privately-held, molecular diagnostic company that has developed the Accula™ System, an affordable, sample-to-answer, CLIA-waived PCR (polymerase chain reaction) testing platform designed specifically for point-of-care (POC) infectious disease diagnosis. Today, Mesa Biotech announced it will present performance comparisons of its visually read PCR testing platform with other FDA-cleared molecular tests for influenza A/B and respiratory syncytial virus (RSV) assays. The lecture will take place on August 6, 2019 at 1:00 pm in theater 3 of the exhibit hall at the 71st American Association of Clinical Chemistry (AACC) Annual Meeting and Clinical Lab Expo in Anaheim, CA. Additionally, the Accula System's RSV and Flu A/Flu B molecular tests will be on exhibit in Booth 3902 at AACC.

"Antiviral drug treatments are becoming increasingly popular and more widely used. The antivirals work best when taken within 48 hours of symptom onset, therefore highly accurate, POC testing is crucial for healthcare professionals to achieve rapid and accurate confirmation of the infection to enable the best patient outcome," said Hong Cai, Co-founder and Chief Executive Officer, Mesa Biotech, Inc.

Stephen Young, PH.D., Director of Research and Clinical Trials at TriCore Reference Laboratory will present the session titled 'Sample-to-answer, CLIA-waived PCR System with Visually Read Results for POC: Comparative Flu and RSV Detection Analysis with Other FDA-cleared Molecular POC Assays'. The presentation will provide a technology overview and performance characteristics of the visually interpreted, CLIA-waived Accula System that possesses the simplicity, convenience and procedural familiarity of traditional POC rapid immunoassays. Additionally, Dr. Young will provide insight on the user experience with the Accula System.

About Mesa Biotech Inc.

Mesa Biotech designs, develops, manufactures and commercializes next generation molecular diagnostic tests, bringing the superior diagnostic performance of nucleic acid PCR amplification to the point-of-care (POC). Mesa Biotech's Accula™ System consists of a portable, palm-sized dock and single-use, assay-specific test cassettes. This patented system enables healthcare professionals to access actionable, laboratory-quality results at the POC with greater sensitivity and specificity than current infectious disease rapid immunoassay tests. The Accula Flu A/Flu B and the Accula RSV tests have obtained CE Mark in the EU and 510(k) clearance and Clinical Laboratory Improvements Amendments (CLIA) waiver from the U.S. Food and Drug Administration (FDA). Both products are distributed in the US by Sekisui Diagnostics under the Silaris™ brand. Mesa Biotech has also secured a number of strategic agreements for distribution in Europe and Asia.

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Using Quantum Dots and a Smartphone to Rapidly Detect Bacterial Pathogens

A combination of off-the-shelf quantum dot nanotechnology and a smartphone camera soon could allow doctors to identify antibiotic-resistant bacteria in just 40 minutes, potentially saving patient lives.

Staphylococcus aureus (golden staph), is a common form of bacterium that causes serious and sometimes fatal conditions such as pneumonia and heart valve infections. Of particular concern is a strain that does not respond to methicillin, the antibiotic of first resort, and is known as methicillin-resistant S. aureus, or MRSA.

Recent reports estimate that 700,000 deaths globally could be attributed to antimicrobial resistance, such as methicillin-resistance. Rapid identification of MRSA is essential for effective treatment, but current methods make it a challenging process, even within well-equipped hospitals.

Soon, however, that may change, using nothing except existing technology.

Researchers from Macquarie University and the University of New South Wales, both in Australia, have demonstrated a proof-of-concept device that uses bacterial DNA to identify the presence of Staphylococcus aureus positively in a patient sample -- and to determine if it will respond to frontline antibiotics.

In a paper published in the international peer-reviewed journal Sensors and Actuators B: Chemical the Macquarie University team of Dr Vinoth Kumar Rajendran, Professor Peter Bergquist and Associate Professor Anwar Sunna with Dr Padmavathy Bakthavathsalam (UNSW) reveal a new way to confirm the presence of the bacterium, using a mobile phone and some ultra-tiny semiconductor particles known as quantum dots.

"Our team is using Synthetic Biology and NanoBiotechnology to address biomedical challenges. Rapid and simple ways of identifying the cause of infections and starting appropriate treatments are critical for treating patients effectively," says Associate Professor Anwar Sunna, head of the Sunna Lab at Macquarie University.

"This is true in routine clinical situations, but also in the emerging field of personalised medicine."

The researchers' approach identifies the specific strain of golden staph by using a method called convective polymerase chain reaction (or cPCR). This is a derivative of a widely -employed technique in which a small segment of DNA is copied thousands of times, creating multiple samples suitable for testing.

Vinoth Kumar and colleagues then subject the DNA copies to a process known as lateral flow immunoassay -- a paper-based diagnostic tool used to confirm the presence or absence of a target biomarker. The researchers use probes fitted with quantum dots to detect two unique genes, that confirms the presence of methicillin resistance in golden staph

A chemical added at the PCR stage to the DNA tested makes the sample fluoresce when the genes are detected by the quantum dots -- a reaction that can be captured easily using the camera on a mobile phone.

The result is a simple and rapid method of detecting the presence of the bacterium, while simultaneously ruling first-line treatment in or out.

Although currently at proof-of-concept stage, the researchers say their system which is powered by a simple battery is suitable for rapid detection in different settings.

"We can see this being used easily not only in hospitals, but also in GP clinics and at patient bedsides," says lead author, Macquarie's Vinoth Kumar Rajendran.

Reference:

Vinoth Kumar Rajendran, Padmavathy Bakthavathsalam, Peter L. Bergquist, Anwar Sunna. Smartphone detection of antibiotic resistance using convective PCR and a lateral flow assay. Sensors and Actuators B: Chemical, 2019; 298: 126849

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IIT Guwahati Researchers Develop Tri-Layer Dielectric Organic Field Effect Transistor to Rapidly Detect Bacteria

Indian Institute of Technology Guwahati Researchers have developed a low-cost, hand-held device to detect bacteria. This Research by IIT Guwahati will enable rapid detection of bacteria, which is important not only in healthcare, but also in anti-bioterrorism measures and environmental monitoring applications.

Bacterial infection is a common cause of morbidity and mortality worldwide and despite development of a range of antibiotics, the challenge continues to lie in detecting and diagnosing bacterial infection early on, as present detection techniques tend to be time-consuming.

The research team led by Prof Parameswar K Iyer, Department of Chemistry, and Prof Siddhartha S Ghosh, Department of Biosciences and Bioengineering, IIT Guwahati, has developed this novel, low-cost, bio-compatible sensor that can detect bacteria almost instantaneously without the need for cell culture and microbiological assays. The Organic Field Effect Transistor (OFET)-based bacterial diagnostic device has been shown to have the ability to detect 103 cfu mL-1 of bacteria and distinguish between Gram positive and Gram negative types.

Their work has been patented as well as published in the July 2019 issue of the reputed peer-reviewed Journal of Materials Chemistry A of the Royal Society of Chemistry.

At present, the detection of bacteria in body fluids is done in laboratories. The cells that are derived from the patient are initially cultured or grown so that enough of the bacterial cells are available for microbiological analysis.

Explaining the need to develop faster and easier methods to detect bacteria, Prof. Iyer says, “Current diagnostic processes are frustratingly time-consuming, especially when time is of the essence in administering treatment.” While newly developed techniques such as real time qPCR can detect bacteria faster than conventional assay-based methods, they are restricted by the need for expensive apparatuses and trained personnel. What would be useful are hand-held rapid detection kits like those used for blood sugar monitoring and pregnancy detection.”

The IIT Guwahati team consisting of Dr Anamika Dey, Dr Ashish Singh, Dr Deepanjalee Dutta (all three former PhD scholars from Center for Nanotechnology, IITG), Prof Siddhartha Sankar Ghosh and Prof Parameswar Krishnan Iyer, brings portable bacterial detection kits closer to reality. The sensor detects the charges on the cell walls of bacteria.

Highlighting the functionality of the device, Prof Ghosh said, “It is known that Gram positive bacteria such as S pneumoniae, have different cell wall compositions than Gram negative bacteria such as the common E coli. Such asymmetric cell wall organisations could alter flow of electrons at the channel of OFETs during their detection”.

The important breakthrough by the team was in developing and using an Organic Field Effect Transistor (OFET) to detect this surface charge. The OFET is an electronic device that works on the principle that charges in the vicinity of the channels of certain semiconductors can induce a current in them. Thus, the charges on the surface of the bacterium, induces a current in the OFET, which is registered and read.

The OFET devices developed by the team consists of a unique and hybrid tri-layer dielectric system built on simple glass and flexible PET (a kind of plastic) substrates, and can operate at ultra-low operating voltages. The team has shown that this OFET sensor can not only detect bacteria, but also differentiate between Gram positive and Gram negative bacteria.

“Not only have we shown the sensing capabilities of this portable OFET device, but we have also shown the mechanism by which sensing occurs and elucidated the role of bacterial wall in distinguishing various bacterial types”, added Prof. Iyer on the significance of this latest interdisciplinary research work.

The OFET-based ready-to-use diagnostic tool will facilitate rapid detection and diagnosis at the point of care. The current device is particularly useful for the detection of bacteria primarily for water-borne diseases. These sensors will also be useful in instantaneous detection of time-critical illnesses such as meningitis.

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Luminex Submits ARIES MRSA Assay for FDA Clearance

Luminex Corporation announced that the company submitted the ARIES® MRSA Assay to the U.S. Food and Drug Administration (FDA) for clearance on Friday, June 28, 2019. The assay is a real-time, quantitative polymerase chain reaction (qPCR)-based, in vitro diagnostic test for the direct detection of methicillin-resistant Staphylococcus aureus (MRSA) DNA from nasal swabs in patients at risk for nasal colonization.

"This submission demonstrates our continued dedication to expanding the menu of clinically relevant and high-value tests that support patient care throughout the world on our sample to answer platforms," said Homi Shamir, President and CEO of Luminex. "Our VERIGENE® II GI Flex and RSP Flex submissions, as well as the commercialization of our new SENSIPLEX™ instrument, remain on track with our previously communicated timelines."

According to the U.S. Centers for Disease Control and Prevention, in 2016, there was approximately one case of MRSA for every 30 people in the U.S. This works out to around 10 million cases of MRSA in the U.S. each year.1,2 Rapid molecular tests for organisms such as MRSA have the potential to aid physicians in reigning in the spread of antimicrobial resistance and the associated negative outcomes for both patients and healthcare facilities by reducing the unnecessary use of antimicrobial therapies, thus allowing for more effective patient management.

The Luminex ARIES® System is a sample to answer, real-time system designed to increase laboratory efficiency, ensure result accuracy, and fit seamlessly into the modern laboratory. The system already offers six FDA and seven CE-IVD cleared assays, as well as the ability to run laboratory developed tests. "This assay will add another foundational test to the ARIES® System, increasing its value for customers and patients," said Shamir.

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Chemiluminescence Probes for the Rapid and Sensitive Detection of Salmonella and Listeria

Salmonella and listeria are among the most widely distributed and deadliest causes of foodborne infections. Their rapid and reliable detection on food and industrial food processing equipment is very important. In the journal Angewandte Chemie, scientists have introduced a new, ultrasensitive, chemiluminescence-based method for the direct detection of Salmonella and Listeria monocytogenes. Because of the simplicity and sensitivity, this test is significantly faster than conventional methods and can be carried out in the field.

It is estimated that about a million people per year are infected with salmonella infections in the USA alone. Of these, 380 die. Infections with listeria can also often be fatal. Current testing methods usually require the growth of bacterial cultures in a containment laboratory. A conclusive result based on standard diagnostic techniques generally takes two to six days.

Researchers working with Urs Spitz and Doron Shabat at the University of Tel Aviv, Nemis Technologies AG (Zurich, Switzerland), Zurich University of Applied Sciences, and Biosynth AG (Staad, Switzerland) have now introduced a new and efficient method for the ultrasensitive and significantly faster detection of Salmonella and Listeria. The method is based on chemiluminescence -- the emission of light resulting from a chemical process. The simplicity of the tests allows for both enrichment of the bacteria and their detection in a test tube, with no further sample preparation, so no containment laboratory is required. The chemiluminescence probes have proven to be about 600 times more sensitive than conventional fluorescence probes.

The success of this technique is due to two specially developed probe molecules made by combining a luminescent substance (a phenoxy-dioxetane) with a "trigger." In this form the probe does not light up. The trigger is tailored to the bacteria to be detected: it is recognized by a specific enzyme produced by the pathogen -- a special esterase in the case of Salmonella and a special phospholipase C for Listeria -- that splits it from the luminescent part. This initiates a chemical reaction that causes the luminescent molecule to split off more pieces. The energy released by the reaction is emitted in the form of a very intense green glow. Tests with various bacteria demonstrated that the probe tailored to Listeria test only reacts to Listeria monocytogenes, not to other, non-pathogenic, strains of listeria. The intensity of the glow can be used to quantify the concentration of bacteria. The tests are so sensitive that, for example, a count of ten salmonella can be detected within six hours of enrichment. Even dried bacteria can be swabbed from surfaces and detected.

The researchers are confident that their new method can be used more broadly to develop specific chemiluminescence probes for other bacteria.

Reference

Michal Roth-Konforti, Ori Green, Mario Hupfeld, Lars Fieseler, Nadine Heinrich, Julian Ihssen, Raffael Vorberg, Lukas Wick, Urs Spitz, Doron Shabat. Ultrasensitive Detection of Salmonella and Listeria monocytogenes by Small-Molecule Chemiluminescence Probes. Angewandte Chemie International Edition, 2019; DOI: 10.1002/anie.201904719

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LamdaGen and Arisan Therapeutics Receive a $2 Million NIH SBIR Phase II Grant to Develop a Dual Rapid Point-of-Care Test for Acute Dengue and Zika Viral Infections

LamdaGen Corporation and Arisan Therapeutics announced today they will share a $2 million Phase II Small Business Innovation Research (SBIR) grant from the National Institute of Allergy and Infectious Diseases, a division of the National Institutes of Health (NIH), to develop a high-sensitivity point-of-care (POC) dual diagnostic to detect both acute dengue and Zika viral infections in a single rapid test on LamdaGen's L'AuRa digital diagnostic platform.

The L'AuRa platform enables robust diagnostic testing that is simple, compact and cost-effective with no moving parts. L'AuRa technology can be integrated into designs ranging from miniaturized handhelds to small desktops to lab-based throughput systems, each providing powerful on-the-spot performance of high-sensitivity, rapid and quantitative diagnostic assays.

Global incidence of dengue has grown dramatically in recent decades with half of the world's population now at risk. In fact, incidence of both dengue and Zika are escalating and prone to unpredictable outbreaks due to climate shifts and proliferation of carriers such as mosquitoes and ticks. Currently, an estimated 390 million dengue infections occur annually. Of these, approximately 500,000 cases develop into life-threatening dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS), severe forms of the disease which result in over 25,000 deaths globally each year.

"Early diagnosis of patients with dengue, in particular, is critical for timely clinical intervention and disease control," commented Randolph Storer, CEO of LamdaGen. "Dengue and Zika are closely related and currently there is no FDA-approved multiplex POC test that can differentiate between the two during the acute phases of infection. Our collaborators at Arisan have identified highly specific antibodies for each test, which we are integrating into the development on the L'AuRa platform."

In addition to enabling differentiation between the two viruses, this highly sensitive and quantitative POC assay will have the potential to act as a prognostic for identifying patients at risk of developing severe forms of dengue including DHF and DSS based on concentration of viral antigen found in blood. Early identification of at-risk patients may help reduce mortality and morbidity by enabling immediate monitoring and medical care.

Speaking of the importance of this NIH grant, Ken McCormack, president of Arisan, added, "We are very appreciative of NIH's support and excited to move forward in our collaboration with LamdaGen to develop these potentially life-saving solutions."

About LamdaGen Corporation

Based in Menlo Park, California, LamdaGen is a developer of nano-based plasmonic biosensors and robust diagnostic systems. The company is increasing access to healthcare with its L'AuRa diagnostic platform, a game-changing technology. L'AuRa is an immuno-based platform that combines the high sensitivity and precision of ELISA with the simplicity and speed of lateral flow to enable quantitative and rapid detection of diseases, pathogens and contaminants. LamdaGen licenses its L'AuRa technology to companies in the human diagnostic, companion animal and food safety industries.

About Arisan Therapeutics Inc.

A privately held life science company based in San Diego, California, Arisan was founded to develop therapeutics for neglected and emerging viral diseases, focusing on infectious diseases with the potential for significant impact on public health and those classified as priority biodefense-related pathogens. The company's mission is to identify unmet medical needs and provide appropriate solutions through development, collaboration and partnerships to benefit patients with life-threatening infectious diseases.

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New Rapid Test Significantly More Effective for TB-diagnosis in People with HIV

A new study has shown a new point-of-care (POC) device to diagnose tuberculosis (TB) in people living with HIV to be substantially (28%) more effective at identifying TB-positive patients than the only POC TB diagnostic device currently available, Alere Determine TB LAM Ag (AlereLAM).

The new Fujifilm SILVAMP TB LAM (FujiLAM) device was shown to be more sensitive than the current POC TB test, at 70.4% compared to 42.3%. This means that FujiLAM has the potential to reduce the number of false negative test results (where someone who has TB incorrectly tests negative). The specificity of the two tests, which measures the likelihood of a test returning a false negative result, was comparable at 90.8% for FujiLAM and 95% for AlereLAM.

There is an urgent need for more rapid, point-of-care diagnostic devises for TB. The challenge is especially important for people living with HIV, because sputum-based tests (which detect TB in saliva and mucous) have consistently demonstrated suboptimal results for immunocompromised individuals.

People living with HIV often have extrapulmonary TB, where the infection has affected parts of the body other than the lungs. This is difficult to diagnose with sputum alone, and severely immunocompromised individuals may have trouble producing the sputum needed for a sample.

Instead of using sputum, both FujiLAM and AlereLAM test for TB in samples of urine, detecting lipoarabinomannan a component of a bacterium found in urine and indicative of TB infection. This present study was conducted to assess the diagnostic accuracy of FujiLAM for the detection of active tuberculosis compared with AlereLAM in hospital patients with HIV.

968 patients from three separate cohorts of hospital in-patients living with HIV in South Africa were included in the final analysis. 62% of the patients were later defined as having active TB, 9% were defined as unknown, and 29% were defined as non-TB.

The median patient age was 35, and the median CD4 count was 113 cells per copy in cohort 1, 153 cells per copy in cohort 2 and 59 cells per copy in cohort 3. Just under half (45%) had a previous history of TB. Cohort 3, which had more people with advanced HIV disease than other cohorts, had the highest sensitivity result at 81% compared to the microbiological reference standard.

Among all patients with a CD4 count less than 100 cells per copy, FujiLAM had a sensitivity of 84.2% compared with 57.3% for AlereLAM. Among patients with CD4 counts over 200 cells per copy, sensitivity was 44% and 12.2% respectively.

The findings are backed up by a previous systematic review carried out by the World Health Organization, which found similar sensitivity and specificity results for the AlereLAM device. The authors conclude that the FujiLAM point-of-care assay could save lives by enabling earlier diagnosis of HIV-associated TB in more inpatients than AlereLAM. But before it can be implemented into clinical practice, further research is warranted and outside of a research laboratory setting.

Authors of the present study led by Tobias Broger and Bianca Sossen, comment, “since AlereLAM has demonstrated survival benefit, FujiLAM might potentially further reduce tuberculosis-related mortality in people with HIV.”

“These findings will inform a WHO policy review for lipoarabinomannan-based diagnostic tests of active tuberculosis. Further research, including prospective and operational studies on the FujiLAM assay in settings of intended use and in additional patient populations, including outpatients with HIV, populations without HIV, and paediatric populations, are needed.”

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