Pathogens from Positive Blood Cultures Rapidly Identified

Faster results help clinicians improve antibiotic selection and outcomes for critical infections.

The molecular method uses peptide nucleic acid probes/fluorescence in-situ hybridization (PNA FISH) tests to identify Staphylococci, Enterococci, Gram-negative bacteria, and Candida species. Using a new protocol for PNA FISH turn-around time was reduced from 2.5 hours to 90 minutes by reducing probe hybridization time from 90 to 30 minutes. Clinical validation studies performed at hospitals in the United States and Europe demonstrated that the new protocol maintained very high (> 95%) sensitivity and specificity versus slower, conventional laboratory methods.

PNA molecules are DNA mimics in which the negatively charged sugar-phosphate backbone of DNA is replaced with a noncharged polyamide or "peptide" backbone. PNA probes contain the same nucleotide bases as DNA, adenine (A), cytosine (C), guanine (G), and thymine (T) and follow standard base-pairing rules while hybridizing to complementary nucleic acid sequences.

The synthetic backbone provides PNA probes with unique hybridization characteristics compared to DNA probes. While hybridizing to complementary nucleic acid sequences, DNA probes must overcome a destabilizing electrostatic repulsion between the negatively charged backbones, resulting in slower and weaker binding. Because of the noncharged backbone, PNA probes do not encounter the electrostatic repulsion allowing them to hybridize rapidly and tightly to nucleic acid targets.

AdvanDx (Woburn, MA, USA) launched the fast, 90 minutes protocol for all CE marking in vitro diagnostic (CE-IVD) PNA FISH tests in Europe. The AdvanDx tests provide rapid identification of bloodstream pathogens and help clinicians optimize antibiotic therapy and improve care for patients with critical infections.

Implementation of these tests reduced time to reporting of pathogen identification results by up to 48-72 hours, improved antibiotic selection for patients with bloodstream infections, reduced unnecessary antibiotic use, reduced infection related mortality rates and significantly reduced hospital bed, pharmacy, and laboratory costs. With the shortened protocol, labs will be able to provide results even faster to help clinicians further improve antibiotic prescribing and patient care.

"We are very excited to launch the shortened PNA FISH protocol in Europe," said Thais T. Johansen, president and CEO of AdvanDx. "The faster results will enable laboratories to provide this critical information sooner to clinicians, enabling them to make the most appropriate antibiotic selection and treatment decision as early as possible," Johansen concluded.

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