Rapid real-time nucleic acid sequence-based amplification-molecular beacon platform to detect fungal and bacterial bloodstream infections

Yanan Zhao, Steven Park, Barry N. Kreiswirth, Christine C. Ginocchio, Raphaël Veyret, Ali Laayoun, Alain Troesch, David S. Perlin

Research output: Contribution to journalArticlepeer-review

63 Scopus citations


Bloodstream infections (BSIs) are a significant cause of morbidity and mortality. Successful patient outcomes are diminished by a failure to rapidly diagnose these infections and initiate appropriate therapy. A rapid and reliable diagnostic platform of high sensitivity is needed for the management of patients with BSIs. The combination of an RNA-dependent nucleic acid sequence-based amplification and molecular beacon (NASBAMB) detection system in multiplex format was developed to rapidly detect medically important BSI organisms. Probes and primers representing pan-gram-negative, pan-gram-positive, pan-fungal, pan-Candida, and pan-Aspergillus organisms were established utilizing 16S and 28S rRNA targets for bacteria and fungi, respectively. Two multiplex panels were developed to rapidly discriminate bacterial or fungal infections at the subkingdom/ genus level with a sensitivity of 1 to 50 genomes. A clinical study was performed to evaluate the accuracy of this platform by evaluating 570 clinical samples from a tertiary-care hospital group using blood bottle samples. The sensitivity, specificity, and Youden's index values for pan-gram-positive detection and pan-gram-negative detection were 99.7%, 100%, 0.997 and 98.6%, 95.9%, 0.945, respectively. The positive predictive values (PPV) and the negative predictive values (NPV) for these two probes were 100, 90.7, and 99.4, 99.4, respectively. Pan-fungal and pan-Candida probes showed 100% sensitivity, specificity, PPV, and NPV, and the pan-Aspergillus probe showed 100% NPV. Robust signals were observed for all probes in the multiplex panels, with signal detection in <15 min. The multiplex real-time NASBA-MB assay provides a valuable platform for the rapid and specific diagnosis of bloodstream pathogens, and reliable pathogen identification and characterization can be obtained in under 3 h.

Original languageEnglish (US)
Pages (from-to)2067-2078
Number of pages12
JournalJournal of clinical microbiology
Issue number7
StatePublished - Jul 2009

All Science Journal Classification (ASJC) codes

  • Microbiology (medical)

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