Thursday, October 6, 2016
In the early stages, serious infections such as meningitis, pneumonia, kidney or bone infections, or dangerous inflammations of the skin, have symptoms that resemble those of more common viral infections. They are also very rare. 'As a result, serious infections tend to stay off the general practitioner's radar for too long. We asked ourselves how rapid diagnostic tests might help solve this problem,' said Dr Verbakel, who is also a Belgium-based GP and a postdoctoral researcher at KU Leuven Faculty of Medicine, where the clinical study was carried out.
The rapid point-of-care blood test for the inflammatory marker C-reactive protein (CRP) takes only four minutes and, in this study, was able to rule out serious infection in nearly 40% of children who presented as being at-risk by the usual clinical assessment. This includes at least one of the following symptoms: breathlessness, a temperature of 40°C and above, or diarrhoea if the child is aged between 12-30 months.
In their randomised trial involving 78 general practices and 3,100 unwell children across Flanders in Belgium, the researchers showed that the usual clinical assessment would flag 57 children for referral to hospital, out of which only one would be found to have a serious infection. Including the CRP test in these cases could reduce the number of referrals to 35.
Dr Verbakel said: 'Point-of-care CRP testing cannot replace a general practitioner. Does the GP sense that something is off? Is the child short of breath, or running a fever of more than 40°C? If the answer to any of these questions is yes, it's useful to perform a point-of-care CRP test. Our study showed that with this procedure, all serious infections were detected during the first visit to the general practitioner. But there's no need to test all ill children.'
He added: 'Thanks to the combination of a clinical examination of the patient, possibly followed by a point-of-care CRP test, general practitioners can detect serious infections more quickly and more objectively. And for children who are less seriously ill, the procedure prevents unnecessary hospital referrals and anxiety. The point-of-care CRP test is a valuable tool for general practitioners, but it has to be used responsibly.'
The paper 'Should all acutely ill children in primary care be tested with point-of-care CRP: a cluster randomised trial' is published in BMC Medicine.
bioMérieux Introduces EviSight™ Compact, a New Automated Diagnostic Solution for Microbial Detection in Pharmaceutical Production
Through kinetic reading, EviSight™ Compact’s high-magnification digital imaging technology provides every 30 minutes high resolution color images of the microbial cultures for colony detection.
Specific algorithms analyze every image and enable the detection of colonies at early growth stages, from a size as small as 30 microns. Openly configurable alert and action level settings allow to raise real time flagging of out of specification results thus saving production time. This new system provides highly reliable results for increased product safety and reduced costs for pharmaceutical companies.
“The EviSight™ Compact platform is the first direct result from the synergies born from the recent acquisition of Advencis by bioMérieux. With an expertise of more than 25 years and a solid position of leadership in the field of industrial microbiological control, we are especially proud to provide our customers from pharmaceutical industry with this pioneering solution which enables rapid and intelligent identification of micro-organisms,” says Michaël Reynier, VP Health & Personal Care Business at bioMérieux. “This innovation further strengthens our portfolio of solutions for the pharmaceutical sector and illustrates our commitment to protecting consumers’ health”.
EviSight™ Compact works with ordinary ready-to-use plates and filters, allowing easy implementation and validation for the daily routine. Its embedded data processing system meets the increasing demand from the pharmaceutical industry for data integrity, traceability and reliability of quality control methods. This compact system can be used at each step of drug development and manufacturing, from the very first stage of R&D to finished products, including growth promotion test, environmental control, water testing and in-process sample testing. The system is scalable to up to 4 units connected to one computer for 6 to 12 plates per unit.
EviSight™ Compact will be progressively rolled out worldwide, starting in: France, the United-Kingdom, Germany, Austria, Switzerland, Italy, Benelux, the U.S., Canada and India.
The global health care community is facing unprecedented challenges with the spread of multidrug resistant organisms, and today’s clinical microbiology laboratories are under increasing pressure to provide fast and accurate bacterial identification and antimicrobial susceptibility testing (ID/AST) results to influence clinical decision and outcomes.
The new BD Phoenix™ M50 ID/AST system helps deliver the same rapid, accurate and cost-effective testing as the legacy BD Phoenix™ 100, within a smaller footprint. The system is highly reliable and requires no preventative maintenance, thanks to innovative materials and engineering techniques employed during its development. In addition to being robust, the system offers multiple languages, facilitating even broader adoption in laboratories around the world.
The new system benefits from the demonstrated performance of the legacy BD Phoenix 100 system for detecting current and emerging resistances as well as the extended testing capabilities provided by BD Phoenix™ Emerge AST panel with 136 wells.
The BD Phoenix M50 system also offers integration with multiple other analyzers, including the BD BACTEC™ and BD Bruker™ MALDI Biotyper systems, through BD EpiCenter™ middleware connectivity that enables data traceability and security, paperless workflow and flexible communication capabilities to deliver the efficiencies expected by laboratories of all sizes. The BD Phoenix M50 system joins the overall BD diagnostics portfolio to help drive the transformation of microbiology.
"The small footprint of the BD Phoenix M50 system combined with its demonstrated speed, accuracy and efficiency makes the system an attractive solution for microbiology laboratories around the world," said Dave Hickey, president of Diagnostics Systems for BD. "This launch reinforces the engagement of BD to become more relevant in ID/AST and intensifies its support to the fight against antimicrobial resistance."
In a paper online this week in Science Advances, Rice's research team used lab tests to verify that UMD could identify 11 known strains of bacteria using the same five random DNA probes. Because the probes are not specific to a particular disease, the technology provides a genomic-based bacterial identification system that does not require a one-to-one ratio of DNA probes to pathogenic species.
"If a laboratory today wants to test for 200 known pathogenic species, they need 200 different tests, each with its own specific DNA probe that was designed specifically to bind with DNA from a particular pathogen," said study co-author Richard Baraniuk, the lead scientist on the new study. "Our technology is fundamentally different. With a small set of DNA probes, we can test for a large number of species."
The new study includes several computer simulations, including one that shows how a random selection of five probes can identify 40 different strains of bacteria, and another that demonstrates how the system can accurately differentiate between 24 different species of Staphylococcus.
Baraniuk said UMD could help in treating and limiting the spread of antibiotic-resistant bacteria, which cause at least 2 million infections and 23,000 deaths each year in the United States, according to the Centers for Disease Control and Prevention.
"In many U.S. hospitals, it still takes several days to definitively identify the specific bacterium that's making someone sick," said Baraniuk, Rice's Victor E. Cameron Professor of Electrical and Computer Engineering. "The lack of rapid bacterial diagnostics can promote antibiotic resistance. Having an accurate, efficient and rapid system for identifying infectious pathogens quickly and inexpensively would help, and such a system would also be a valuable tool for public health, defense, global health and environmental science."
Historically, scientists identified bacteria by first culturing a sample—a process that takes several days—and then examining the organism under a microscope. More recent genomic identification methods that use polymerase chain reaction, or PCR, and genomic sequencing can be faster but require expensive equipment and training as well as a specific DNA probe for each pathogen to be tested. The probes are snippets of complementary DNA from a known disease. If the DNA from a patient's sample binds with the complementary DNA in a disease probe, the diagnosis is positive for that disease.
"Probe A is only good for finding bacterium A, and probe B is only good for finding bacterium B," said study lead author Amirali Aghazadeh, a graduate student in electrical and computer engineering in Baraniuk's lab. "Manufacturing such a probe for a new disease can take days to months and also requires expensive facilities that are only available in developed countries.
"With universal microbial diagnostic, we won't need new probes or to change any other parts of the sensing hardware," he said. "For any newly discovered bacterial strain, we can just adapt the software a little bit, and then the same platform can identify the new bacterium like any other."
Rather than identifying a target strain based on a 100 percent match with a specific probe, Rice's system tests how well the target DNA binds with several different random segments of complementary DNA. UMD uses a mathematical technique called compressive sensing, which was pioneered in the field of digital signal processing. With compressive sensing, the disease DNA need not bind with 100 percent of the probes. Instead, the UMD system measures how well the disease DNA binds with each of the random probes and creates a specific binding profile for the test organism. It then uses deductive reasoning to determine whether that profile matches the profile of any known pathogens.
"We believe the system will be most useful for rapidly and accurately looking for known targets, such as any organism on the World Health Organization's list of known pathogens, but another advantage of this method is that we get useful information even for organisms that have never been sequenced before," said study co-author Rebekah Drezek, professor of bioengineering and of electrical and computer engineering. "We'd be able to tell what pathogen a new disease is most closely related to."
A team led by Prof. Ashis Kumar Sen, the corresponding author of the paper from the Department of Mechanical Engineering, IIT Madras, used a 2-cm-long microchannel device that employs capillary force to draw blood into the device to separate plasma from whole blood and test glucose level in diabetic patients.
The first part of the microchannel device has hydrophilic walls (top and two side walls) that help the blood sample to be drawn in through capillary force. But one centimetre away, all the four walls of the microchannel are hydrophobic. Like a drop of water on a Teflon surface, the blood comes together and forms a large contact angle (more than 90 degrees) when it enters the hydrophobic region. The forward movement of the blood is suddenly impeded and the blood cells tend to accumulate in the hydrophobic region of the microchannel.
Unlike blood cells, the plasma with its low viscosity continues to move forward due to the momentum gained while passing through the hydrophilic region. “The blood cells slow down and then stop moving at the hydrophobic region and form a self built-in filter, while the plasma continues to move past the cells,” says Prof. Sen. “By creating a differential wetting behaviour in the microchannel we were able to separate the plasma from the blood cells.” Separating the plasma from blood cells is essential as it improves sensitivity and reliability. Most blood analyses are based on optical detection techniques, and blood cells present tend to interfere with the optical path resulting in low sensitivity.
The device does not require any external or internal power as it relies on capillary force to draw blood and the separation of plasma from blood cells is achieved through differential wetting behaviour of the microchannel walls.
“Only 5 microlitre of blood is required and in 15 minutes we get 450 nanolitre of plasma which further increases with time. With suitable design modifications we have also achieved higher plasma volume up to 2 microlitre in 15 min, which is adequate for detection of most analytes,” says M. Sneha Maria, the first author of the paper from the Department of Mechanical Engineering and Department of Biotechnology, IIT Madras. It takes 15-20 minutes to test the samples and get the results.
The detection platform for different diseases and conditions can be integrated within the device inside the hydrophobic region. “This is a proof-of-concept study so we used commercially available glucose test strips to detect glucose level in the blood samples,” says Ms. Maria. The sensitivity of the disposable device is comparable to conventional blood tests, says Prof. Sen.
Unlike the microchannel device used by the IIT team, many commercial glucometers rely on whole blood for testing. Using whole blood can cause measurement errors due to various hematocrit levels (the ratio of the volume of red cells to the volume of whole blood). When the hematocrit levels are high the viscosity of blood is more and this leads to low glucose concentration and underestimation. Overestimation results when the hematocrit levels are low. “There is a likelihood of more than 10 per cent error in glucose detection when whole blood is used,” says Ms. Maria.
The team is now testing the device for diagnosis of dengue. Currently, rapid diagnostic test kits either use whole blood which affects the sensitivity or centrifuged plasma for dengue detection. This is where the device can score over others. Prof. Sen is hopeful that the device can be used for parallel detection of analytes for several diseases using just one blood sample. “We intend to separate the plasma to multiple detection sites for studying several diseases in one go,” he says.
The new wireless BD Veritor™ Plus System provides health care providers and laboratorians in physician offices, clinics, hospitals and integrated delivery networks (IDNs) with objective, lab-quality immunoassay test results within minutes. This rapid and accurate solution streamlines the point-of-care (POC) diagnostic workflow and enables providers to quickly review patient results to assist in determining the appropriate treatment in a single consultation. The system can help detect influenza A and B, respiratory syncytial virus (RSV) and group A strep while the patient is still on site, which enables faster decision making for an earlier intervention opportunity.
The BD Veritor Plus System benefits from the demonstrated performance of the legacy BD Veritor System and offers new features to improve quality control (QC) by identifying QC results. The enhanced documentation functionality includes user ID, specimen ID and test kit lot to improve traceability, which decreases manual documentation.
The new BD Veritor Plus System also offers the BD Cloud Connectivity Solution ― a technology that allows users to wirelessly transfer test data securely to an electronic medical record (EMR) or a laboratory information system (LIS) to enable data access across an entire IDN. This can help to reduce potential errors associated with manual documentation and streamlines POC testing workflow to enable physicians to more easily access test results and use the information to determine next steps in patient care.
Millions of people are sickened by influenza in the U.S. each year.i Additionally, most children will have respiratory syncytial virus (RSV) by the time they are twoii and 20 percent to 30 percent of sore throats in children are caused by group A Streptococcus.iii The BD Veritor Plus System, with enhanced features, can aid in the diagnosis of these disease states.
"As we are on the cusp of the flu season, it is critical that providers have the diagnostic tools they need to assist them in quickly and accurately identifying infectious diseases, like flu, RSV and strep and in assigning treatment protocols," said Dave Hickey, president of Diagnostic Systems at BD. "The BD Veritor Plus System's ability to provide reliable test results and wirelessly transfer them to health records could ultimately lead to better outcomes through rapid detection and simplified workflow."
Salmonella is the lauding cause of bacteria-associated foodborne illnesses in the United States, according to the study. Thus, early detection of the pathogen, by a rapid and sensitive test is important to prevent the illness.
In a newly published study, researchers artificially contaminated food with salmonella. They then tested the food samples using Salmonella-specific antibodies combined with a unique signal amplification technique. Their test found salmonella present after 15 hours and removed other microorganisms that sometimes clutter laboratory results. This is shorter than the two to three days it takes to detect salmonella in a culture, the study shows.
"The test has great potential as a simple monitoring system for foodborne pathogens in food samples, which can improve food safety and public health," said Soohyoun Ahn, a UF/IFAS assistant professor of food science and human nutrition and lead author of the study. "Even with all the strategies used to minimize contamination of beef and poultry, they are still one of the major food vehicles for salmonella."
The test would be suitable for any government research laboratory or industry that routinely tests for Salmonella, Ahn said.
Contamination of foodborne pathogens causes an estimated 48 million illnesses, 128,000 hospitalizations and 3,000 deaths annually in the United States, according to a U.S. Centers for Disease Control report in 2011.
Ahn sees the salmonella test showing similar potential for faster detection of other pathogens you can get from eating certain contaminated foods. A similar test has been developed for E. coli in milk and ground beef, and it performed well, she said.
The study is published in the Journal of Food Safety:
Gene P. D. Herzig, Muhsin Aydin, Samantha Dunigan, Parth Shah, Kwang Cheol Jeong, Si Hong Park, Steven C. Ricke, Soohyoun Ahn. Magnetic Bead-Based Immunoassay Coupled with Tyramide Signal Amplification for Detection ofSalmonellain Foods. Journal of Food Safety, 2016; 36 (3): 383 DOI: 10.1111/jfs.12255