Physician

GNR - EK/P. aeruginosa PNA FISH

For in vitro diagnostic use.

EK/P. aeruginosa PNA FISH® (Cat. No. KT008) is a multicolor, qualitative nucleic acid hybridization assay intended for identification of E. coli and/or K. pneumoniae and P. aeruginosa on smears from positive blood cultures containing Gram-negative rods. The EK/P. aeruginosa PNA FISH assay is indicated for use in conjunction with positive blood subcultures as an aid in the identification of E. coli/K. pneumoniae and/or P. aeruginosa.

EK/P. aeruginosa PNA FISH provides rapid identification of both E. coli and/or K. pneumoniae and P. aeruginosa on smears made directly from Gram-negative rod (GNR)-positive blood cultures and is compatible with all major blood culture media. The 2.5 hours fluorescence in situ hybridization (FISH) assay uses fluorescently labeled peptide nucleic acid (PNA) probes that target the species-specific ribosomal RNA (rRNA) of E. coli, K. pneumoniae and P. aeruginosa. Results are visualized using fluorescence microscopy. E. coli and/or K. pneumoniae is identified as multiple bright green fluorescent rods in multiple fields of view, whereas P. aeruginosa is identified as multiple bright red fluorescent rods in multiple fields of view. The absence of fluorescence indicates another species is present in the positive blood culture.

Features and Benefits

Results Reporting - Rapid Identification of GNR+ Blood Cultures

Optimizing Antibiotic Therapy for Gram-negative Bloodstream Infections (BSI)

• Provides rapid identification of E. coli/K. pneumoniae and P. aeruginosa from GNR positive blood cultures 24-48 hours sooner than conventional methods
• Helps clinicians optimize therapy for patients with GNR bloodstream infections
• Enables clinical to provide early, appropriate therapy for E. coli/K. pneumoniae and P. aeruginosa infections  

Gram-negative BSIs are considered one of the most serious hospital-acquired infections, accounting for approximately 25% of all BSI’s, afflicting 100,000 patients annually in the US alone. Gram-negative BSIs are associated with high mortality rates and can be difficult to treat due in part to increasing resistance to a multitude of antibiotic agents, especially for P. aeruginosa. Treatment challenges are further compounded by current laboratory testing methods for Gram-negative pathogen identification that can take 24-48 hours, forcing clinicians to treat patients empirically. As a result, a single Gram-negative bacteremia case can result in extra length of stay between 5 and 24 days, costing institutions between $40,000 and $60,000.(1,2)

Early differentiation between these species can improve antibiotic therapy selection as P. aeruginosa species are often highly virulent and frequently multi-drug resistant, where in some cases E. coli and K. pneumoniae species may require less aggressive therapy. Since traditional methods take days to discriminate between these two species, Gram-negative BSI patients are either subject to broader-than-necessary antibiotic therapy increasing resistance and the risk of toxicity complications, or are undertreated, escalating the potential for adverse patient outcomes.(2)

While conventional laboratory methods can take up to 2 days or more, EK/P. aeruginosa PNA FISH enables microbiology labs to provide clinicians rapid, accurate species identification results in hours not days. In addition, rapid identification of E. coli and/or K. pneumoniae may allow laboratories to improve workflow and turn-around times for susceptibility results through earlier initiation of such tests as the Hodge disk-diffusion for carbapenem resistance. Studies show that providing a 24 hours “head start” on appropriate narrow-spectrum therapy for Gram-negative bloodstream infections can improve clinical outcomes, reduce antibiotic resistance rates and reduce the incidences of adverse events (2,3)

This first rapid, molecular diagnostic assay for identification of Gram-negative rod species from positive blood cultures will enable clinicians to ensure early and appropriate treatment for patients with Gram-negative bloodstream infections.   

1. Kang et al. Bloodstream Infections Caused by Antibiotic-Resistant Gram-Negative Bacilli: Risk Factors for Mortality and Impact of Inappropriate Initial Antimicrobial Therapy on Outcome. Antimicrobial Agents and Chemotherapy. 2005 Feb; 49:760-766 - Link
2. Slama et al. Gram-negative antibiotic resistance: there is a price to pay. Critical Care. 2008 May;12 Sup 4:1-9 - Link
3. Thom et al. Impact of Empiric Antimicrobial Therapy on Outcomes in Patients with Escherichia coli and Klebsiella pneumoniae Bacteremia: A Cohort Study. BMC Infectious Diseases. 2008 Sept; 8(116) - Link

PN1623A