Rapid identification of Staphylococcus aureus directly from blood cultures by fluorescence in situ hybridization with peptide nucleic acid probes.
A new fluorescence in situ hybridization (FISH) method with peptide nucleic acid (PNA) probes for identification of Staphylococcus aureus directly from positive blood culture bottles that contain gram-positive cocci in clusters (GPCC) is described. The test (the S. aureus PNA FISH assay) is based on a fluorescein-labeled PNA probe that targets a species-specific sequence of the 16S rRNA of S. aureus. Evaluations with 17 reference strains and 48 clinical isolates, including methicillin-resistant and methicillin-susceptible S. aureus species, coagulase-negative Staphylococcus species, and other clinically relevant and phylogenetically related bacteria and yeast species, showed that the assay had 100% sensitivity and 96% specificity. Clinical trials with 87 blood cultures positive for GPCC correctly identified 36 of 37 (97%) of the S. aureus-positive cultures identified by standard microbiological methods. The positive and negative predictive values were 100 and 98%, respectively. It is concluded that this rapid method (2.5 h) for identification of S. aureus directly from blood culture bottles that contain GPCC offers important information for optimal antibiotic therapy.
Oliveira
Kenneth
K
Boston Probes, Inc., Bedford, Massachusetts 01730, USA.
Procop
Gary W
GW
Wilson
Deborah
D
Coull
James
J
Stender
Henrik
H
D001769:Blood / Q000382:microbiology*; D003470:Culture Media; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D015341:Nucleic Acid Probes; D020135:Peptide Nucleic Acids / Q000235:genetics*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012680:Sensitivity and Specificity; D013203:Staphylococcal Infections / Q000382:microbiology; D013211:Staphylococcus aureus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D013997:Time Factors
D003470:Culture Media; D015341:Nucleic Acid Probes; D020135:Peptide Nucleic Acids; D012336:RNA, Ribosomal, 16S