AdvanDx announced that it has submitted to the U.S. Food and Drug Administration for 510(k) clearance its new mecA XpressFISH™ test for the rapid detection of methicillin-resistant Staphylococcus aureus (MRSA) from S. aureus positive blood cultures.
Methicillin-resistant Staphylococcus aureus (MRSA) is resistant to antibiotics commonly used to treat ordinary staphylococcal infections. An estimated 80,461 invasive MRSA infections occurred in the U.S. in 2011. Of these, 48,353 were healthcare associated community onset infections; 14,156 were hospital-onset infections; and 16,560 were community-associated infections.(1)
Methicillin-resistance is almost exclusively caused by the presence and expression of the mecA gene that encodes a unique penicillin-binding protein (PBP2a) that has low affinity for methicillin and other b-lactam drugs.mecA XpressFISH is a qualitative fluorescence in situ hybridization (FISH) assay that utilizes peptide nucleic acid (PNA) probes hybridizing to mecA messenger RNA (mRNA) sequences on smears from blood cultures containingStaphylococcus aureus (SA). This “phenotypic” mRNA-targeting approach makes XpressFISH unique in its mechanism of MRSA identification.
“This is a significant breakthrough in how we identify MRSA,” says James M. Coull, Ph.D, Chief Technology Officer for AdvanDx. “By targeting mecA mRNA, mecA XpressFISH rapidly detects the presence of the mecAgene, and determines whether the gene is transcriptionally functional and therefore able to confer resistance to broad classes of antibiotics, such as penicillins and cephalosporins. This information should help clinicians quickly determine the best course of antibiotic treatment.”
Although identification of MRSA is used to guide effective therapy, conventional laboratory methods can take 48 hours to determine whether S. aureus bacteria are resistant. mecA XpressFISH will enable laboratories to rapidly detect MRSA directly from S. aureus positive blood cultures in about an hour. The rapid determination of MRSA by mecA XpressFISH should enable clinicians to prescribe more effective appropriate therapy sooner for MRSA-infected patients.
A Proven Track Record with Staphylococcal Bloodstream Infections
mecA XpressFISH is the latest addition to AdvanDx’s easy-to-use, molecular-based diagnostics platform that provides rapid identification of bloodstream pathogens in minutes instead of days. AdvanDx also markets theQuickFISH platform for rapid identification of Gram-positive and Gram-negative bacteria as well as PNA FISH forCandida species.
Since 2003, the use of AdvanDx’s flagship product, PNA FISH for rapid identification of staphylococcal bloodstream pathogens has dramatically improved therapy decisions and outcomes for patients with bloodstream infections by helping physicians and pharmacists optimize antibiotic therapy earlier. A clinical study performed at the Washington Hospital Center (Washington, D.C.) demonstrated that rapid identification and notification of PNA FISH results reduced ICU and overall mortality rates by 82% and 53% respectively, while reducing antibiotic use for patients with CNS positive blood cultures. In a separate study performed at the University of Maryland Medical Center (Baltimore, MD) rapid PNA FISH results, helped reduce unnecessary vancomycin use by 4.5 doses, length of stay by 2 days and hospital costs by $4,005 for patients with CNS contaminated blood cultures. (2,3)
1. JAMA National Burden of Invasive Methicillin-Resistant Staphylococcus aureus Infections, United States, 2011
2. Ly et al. Ther Clin Risk Manag. 2008 Jun;4(3):637-40.
3. J Antimicrob Chemother. 2006 Jul;58(1):154-8.