AdvanDx announces that a new medical study demonstrated use of its PNA FISH™ test reduced mortality by 42% for patients with highly drug resistant Hospital-Acquired Enterococcus faecium bloodstream infections (BSIs). In addition, the study demonstrated that PNA FISH reduced the time to reporting of laboratory identification results for all enterococcal BSIs by 2.6 days and reduced time to appropriate antimicrobial therapy for E. faecium BSIs by 1.8 days. The study was undertaken by clinicians at the University of Maryland Medical Center (UMMC) in Baltimore, Maryland and published in the latest issue of Antimicrobial Agents and Chemotherapy.
Bloodstream infections due to Enterococcus bacteria, predominantly Enterococcus faecalis and E. faecium, are often acquired while patients are in the hospital and can lead to increased mortality, longer hospital stays and increased healthcare costs. The infection is initially diagnosed when a culture of the patient’s blood turns positive with Gram-positive cocci in pairs and chains (GPCPC), indicative of enterococci and/or streptococci.
Because conventional laboratory identification methods can take 48 hours or longer and early antimicrobial therapy is crucial to ensure positive patient outcomes, physicians often prescribe broad-spectrum antibiotics such as vancomycin to cover the patient. However, this may lead to the administration of inadequate or inappropriate antibiotic treatment as E. faecium is often resistant to both vancomycin (VRE – vancomycin-resistant enterococci) and penicillin-based drugs such as ampicillin while E. faecalis is often susceptible to ampicillin.
PNA FISH delivers rapid, molecular identification of E. faecalis and other enterococci, including E. faecium, directly from GPCPC positive blood cultures in hours instead of days. As a result, laboratories can provide faster information that enables clinicians to select effective antibiotic therapy sooner for patients afflicted with enterococcal bloodstream infections.
The study included 224 patients with hospital-acquired enterococcal bloodstream infections; 112 patients before the PNA FISH test was implemented (Pre-PNA FISH group) and 112 after implementation (PNA FISH group). A treatment algorithm based on the rapid PNA FISH results was developed and implemented by the hospital’s antimicrobial management team. Patients with E. faecalis by PNA FISH were to be given ampicillin, while patients with other enterococci, including E. faecium, and at "high risk" for VRE were to be given linezoid, a newer anti-VRE antibiotic. At the end of the study, data on characteristics, therapy and outcomes between the Pre-PNA FISH and PNA FISH patients groups were compared.
Significant UMMC Study Data (Pre-PNA FISH vs. PNA FISH Groups)
- More than 88% of all E. faecium were resistant to vancomycin (VRE) and
- 100% were resistant to ampicillin
- 84% of initial empirical antimicrobial therapy for patients with E. faecium BSIs was inadequate
- 2.6 days reduction in time to laboratory identification results in PNA FISH group
- 1.8 days reduction in time to appropriate antimicrobial therapy for E. faecium in PNA FISH group
- 42% reduction in 30-day mortality rates for patients with E. faecium in PNA FISH group
- PNA FISH Sensitivity, Specificity, Positive Predictive Value and Negative Predictive Value shown to be 100% compared to conventional methods
"Use of PNA FISH in conjunction with a treatment algorithm led to earlier identification of the Enterococcus species for patients with hospital-acquired enterococcal bloodstream infections and the earlier initiation of effective antimicrobial therapy for patients with hospital-acquired E. faecium bloodstream infections," said Dr Graeme Forrest, Division of Infectious Diseases, University of Maryland Medical Center and lead author of the study.
"We are very excited to see the results from the University of Maryland Medical Center study. Not only do they show that PNA FISH significantly speeds up species identification results from the lab, but also that using the results to tailor therapy at an earlier stage in bloodstream infections can significantly improve patient care and outcomes," said Thais T Johansen, President and CEO of AdvanDx.
"If we extrapolate the data to the rest of the country, PNA FISH could help ensure that all of the 18,000 patients with hospital-acquired enterococcal bloodstream infections receive effective antibiotic therapy as early as possible and help save close to 2,000 lives. In essence, implementing PNA FISH and providing rapid results to clinicians could be more beneficial than any new antibiotic to treat the infections," Johansen added.