Biomaterial Database

Evaluation of three rapid methods for the direct identification of Staphylococcus aureus from positive blood cultures. 2003

Kimberle Chapin, and Michael Musgnug

Lahey Clinic, Burlington, Massachusetts 01805, USA. Kimberle_c_chapin@lahey.org

Staphylococci represent the most commonly encountered blood culture isolates. Differentiating Staphylococcus aureus from coagulase-negative staphylococci (CoNS) is important in guiding empirical therapy, especially since the majority of CoNS are contaminants. This study evaluated three rapid methods for the direct identification of S. aureus from blood cultures. A total of 157 patient blood cultures with gram stains showing gram-positive cocci in clusters were included. The following assays were evaluated: API RAPIDEC staph (API) (bioMerieux, Durham, N.C.), the tube coagulase test (TCT) read at 4 h, and peptide nucleic acid (PNA) fluorescence in situ hybridization (FISH) (AdvanDx, Woburn, Mass.). All assays yielded results of S. aureus or non-S. aureus. The direct rapid results were compared to results obtained with isolated colonies using the AccuProbe Staphylococcus aureus Culture Identification Test (Gen-Probe, San Diego, Calif.). API, TCT, and PNA FISH exhibited sensitivities of 96, 84, and 99% and specificities of 99, 100, and 100%, respectively. Direct identification testing by any of these three assays yielded acceptable performance and timely results. This ability to accurately detect S. aureus in blood cultures gives the physician information with which to initiate or tailor antimicrobial therapy. Coupled with direct susceptibility testing of positive blood culture broths, the patient and institution may experience improved outcomes.

UI	MeSH Term	Description	Entries
D003030	Coagulase	Enzymes that cause coagulation in plasma by forming a complex with human PROTHROMBIN. Coagulases are produced by certain STAPHYLOCOCCUS and YERSINIA PESTIS. Staphylococci produce two types of coagulase: Staphylocoagulase, a free coagulase that produces true clotting of plasma, and Staphylococcal clumping factor, a bound coagulase in the cell wall that induces clumping of cells in the presence of fibrinogen.	Staphylocoagulase,Staphylococcal Clumping Factor,Clumping Factor (Staphylococcal),Staphylococcus aureus clone pSCa2 of Coagulase,Staphylococcus aureus strain 213 of Coagulase,Staphylococcus aureus strain 8325-4 of Coagulase,Clumping Factor, Staphylococcal,Factor, Staphylococcal Clumping,Staphylococcus aureus strain 8325 4 of Coagulase
D003365	Costs and Cost Analysis	Absolute, comparative, or differential costs pertaining to services, institutions, resources, etc., or the analysis and study of these costs.	Affordability,Analysis, Cost,Cost,Cost Analysis,Cost Comparison,Cost Measures,Cost-Minimization Analysis,Costs and Cost Analyses,Costs, Cost Analysis,Pricing,Affordabilities,Analyses, Cost,Analyses, Cost-Minimization,Analysis, Cost-Minimization,Comparison, Cost,Comparisons, Cost,Cost Analyses,Cost Comparisons,Cost Measure,Cost Minimization Analysis,Cost, Cost Analysis,Cost-Minimization Analyses,Costs,Measure, Cost,Measures, Cost
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D001431	Bacteriological Techniques	Techniques used in studying bacteria.	Bacteriologic Technic,Bacteriologic Technics,Bacteriologic Techniques,Bacteriological Technique,Technic, Bacteriological,Technics, Bacteriological,Technique, Bacteriological,Techniques, Bacteriological,Bacteriologic Technique,Bacteriological Technic,Bacteriological Technics,Technic, Bacteriologic,Technics, Bacteriologic,Technique, Bacteriologic,Techniques, Bacteriologic
D013211	Staphylococcus aureus	Potentially pathogenic bacteria found in nasal membranes, skin, hair follicles, and perineum of warm-blooded animals. They may cause a wide range of infections and intoxications.
D016470	Bacteremia	The presence of viable bacteria circulating in the blood. Fever, chills, tachycardia, and tachypnea are common acute manifestations of bacteremia. The majority of cases are seen in already hospitalized patients, most of whom have underlying diseases or procedures which render their bloodstreams susceptible to invasion.	Bacteremias
D017404	In Situ Hybridization, Fluorescence	A type of IN SITU HYBRIDIZATION in which target sequences are stained with fluorescent dye so their location and size can be determined using fluorescence microscopy. This staining is sufficiently distinct that the hybridization signal can be seen both in metaphase spreads and in interphase nuclei.	FISH Technique,Fluorescent in Situ Hybridization,Hybridization in Situ, Fluorescence,FISH Technic,Hybridization in Situ, Fluorescent,In Situ Hybridization, Fluorescent,FISH Technics,FISH Techniques,Technic, FISH,Technics, FISH,Technique, FISH,Techniques, FISH
D020135	Peptide Nucleic Acids	DNA analogs containing neutral amide backbone linkages composed of aminoethyl glycine units instead of the usual phosphodiester linkage of deoxyribose groups. Peptide nucleic acids have high biological stability and higher affinity for complementary DNA or RNA sequences than analogous DNA oligomers.	Peptide Nucleic Acid,Acid, Peptide Nucleic,Acids, Peptide Nucleic,Nucleic Acid, Peptide,Nucleic Acids, Peptide