AdvanDx (Woburn, Massachusetts) reported receiving FDA 510(k) clearance for E. coli/P. aeruginosa PNA FISH to identify Escherichia coli and/or Pseudomonas aeruginosa directly from positive blood cultures. According to the company, the new diagnostic is the first test for identifying E. coli and P. aeruginosa directly from positive blood cultures and the latest addition to AdvanDx's molecular-based PNA FISH diagnostics platform.

PNA FISH tests now provide rapid species identification for the "vast majority" of Gram-stain results in hours instead of days, AdvanDx noted.

Joen Johansen, director of marketing at AdvanDx, told Diagnostics & Imaging Week that with the addition of this test, the company's PNA FISH diagnostic platform now provides a complete solution by enabling rapid identification results for 95% to 98% of all patients with positive blood cultures instead of just 65% to 70% as was covered previously.

Every year nearly 100,000 patients develop bloodstream infections due to Gram-negative pathogens such as E. coli and/or P. aeruginosa. Patients afflicted by these serious infections spend an average of five to 24 days in the hospital, suffer mortality rates as high as 40% and cost institutions on average $40,000 to $60,000 per case, the company said.

According to AdvanDx, these grim statistics are due in part to Gram-negative bacteria's increasing resistance to a multitude of antibiotic agents, especially in P. aeruginosa, creating complex therapy decisions for clinicians. But wait, it gets worse.

Conventional laboratory testing methods for Gram-negative pathogens can take up to 48 hours to provide results, forcing clinicians to treat patients empirically (in other words, by observation or experimentation) which may not provide full coverage for the infecting pathogen.

Providing a 24-hour head start on appropriate narrow-spectrum therapy for Gram-negative bloodstream infections may improve clinical outcomes, reduce antibiotic resistance rates and reduce the incidences of adverse events, the company noted.

E. coli/P. aeruginosa PNA FISH will, for the first time, enable microbiology labs to provide clinicians rapid, accurate Gram-negative pathogen identification in hours, not days, AdvanDx said.

These organisms, E. coli and P. aeruginosa, are more complex than other bloodstream infections, such as staphylococcal, Johansen said, in that physicians have a much tougher time treating them with antibiotics. "They don't know exactly how to cover the patients with the right antibiotics," he said. This new PNA FISH test narrows down the spectrum of antibiotics, he added.

When a hospitalized patient is identified as having a bloodstream infection, finding out which type of infection it is – and subsequently which antibiotic should be used to fight it off – is critical.

"By the time a patient is sick enough to have a bloodstream infection they are already in the hospital," Johansen said. If not treated quickly enough, the infection can kill the patient, he added.

Johansen said the PNA FISH test speeds up results by 24 to 48 hours, depending on the methods that the laboratory uses. But speed isn't the only thing that is critical here. These rapid tests provide results quickly without losing accuracy, he said.

In July, AdvanDx reported a study that shows use of its PNA FISH test was associated with an 82% reduction in mortality rates from S. aureus bloodstream infections in the ICU, a 53% reduction in overall mortality from staphylococcal bloodstream infections and a significant reduction in antibiotic use. As with the E. coli/P. aeruginosa PNA FISH test, that rapid test also allows microbiology labs to report identification results to physicians within a few hours of a blood culture turning positive.

AdvanDx has seven PNA FISH tests already on the market and two more under review by FDA, Johansen said. One of the products under review is a test for Group B Strep in pregnant women, a type of bacterial infection that can be passed to a baby during delivery.

"We are very excited to launch E. coli/P. aeruginosa PNA FISH as another critical tool to help laboratories and clinicians provide faster results and improve care for patients with life threatening infections," said Thais Johansen, president/CEO of AdvanDx.