The test is much faster than current laboratory techniques, and can pickup on signs of bacterial growth within hours of the infection starting. Current tests require waiting as long as four days, which obviously exposes the patient to a longer wait time and risk, whilst giving the disease more time to establish itself.
The test, known as the Verigene GP Blood Culture Nucleic Acid Test (BC-GP) is able to identify different types of Staphylococcus, (including methicillin-resistant Staphylococcus aureus or MRSA), Streptococcus, Enterococcus (including vancomycin-resistant Enterococci or VRE), and Listeria.
Alberto Gutierrez, director of the Office of In Vitro Diagnostic Device Evaluation and Safety at the FDA's Center for Devices and Radiological Health said:
Bloodstream infections are always treated with antimicrobial drugs, and it is essential to identify which antimicrobial drug is appropriate for a specific patient as quickly as possible ... This new test is an important tool that will help physicians treat patients quickly with the correct antibiotics."
The tests, developed by Nanosphere Inc. of Northbrook, IL, are considered an important breakthrough because bacterial infection is becoming increasingly resistant to antibiotics. Delayed administration of antibiotics has been linked with more than 7% decrease in survival rate for each hour the therapy is delayed. Not only that, by indentifying and treating the infection faster, hospital costs are reduced, with estimated savings of up to $21,000 per patient. The fast turn-around time of the test, which is based on molecular testing rather than trying to identify the pathogen in whole, also makes doctors and nurses jobs much easier and more efficient.
Nanosphere is in the process of developing a disease test menu that will give physicians automated detection all on the same automated platform. The gram-negative blood cultures will provide genus, species, and resistance detection. In 2011, the FDA approved Nanosphere's multiplexed Verigene RV+ respiratory virus test, which will also be included in the platform. Others said to be included are C. difficile and a panel of enteric bacterial and viral pathogens. Nanoshpere says it plans to apply for FDA clearance on these later in the year.
Blood stream infections and septicemia are two of the most expensive causes of hospitalizations, with estimated costs totaling more than $15 billion per year, from 1.6 million hospitalizations. They are pervasive and aggressive problems with a high mortality rate and urgent treatment is essential to the patient. The inability to correctly identify the pathogens delays correct treatment and can lead to wrong wasteful and unnecessary treatment, but not only that, wrong treatment can help breed more resistant strains of the bacteria and weaken the patient's ability to respond to proper medication after the bacteria are correctly identified.
William Moffitt, Nanosphere's Chief Executive Officer summarizes the FDA announcement by saying:
"With the BC-GP test, patients suspected of deadly infections can now get a first-ever diagnostic tool for detecting disease-causing bacteria while simultaneously determining antibiotic resistance within the critical timeframe for making and adjusting initial treatment."
Written by Rupert Shepherd