AIMS: The Cepheid GeneXpert is a four-site, automated sample preparation and real-time PCR detection system. In this study, the capability of the GeneXpert to isolate and detect nucleic acid from Bacillus anthracis Ames spores was assessed. METHODS AND RESULTS: A four-plex, dried-down bead cartridge containing PCR reagents specific for the pXO1 and pXO2 plasmids as well as sample processing and inhibition controls was evaluated. For B. anthracis Ames spores harbouring pXO1 and pXO2, samples containing 68 CFU per ml (148 spores per ml) were positive in all four replicates. A limited cross-reactivity panel, which included closely related Bacillus species, was also tested to determine the specificity of the pXO1 and pXO2 assays. No cross-reactivity occurred. Further, B. anthracis Sterne spore samples were analysed to compare results when processed using the GeneXpert to those run directly on the Cepheid SmartCycler without sample processing. The GeneXpert detection capability was three logs lower than the SmartCycler indicating the benefit of incorporating a nucleic acid extraction procedure. CONCLUSIONS: This study demonstrates that the GeneXpert is a rapid and reliable system for simultaneously detecting the B. anthracis virulence plasmids pXO1 and pXO2. SIGNIFICANCE AND IMPACT OF THE STUDY: The GeneXpert is the only platform currently available that is capable of both nucleic acid purification and real-time PCR detection enclosed within a single system. Further, all sample manipulations are automated, thus reducing errors associated with manual processing.
AIMS: The Cepheid GeneXpert is a four-site, automated sample preparation and real-time PCR detection system. In this study, the capability of the GeneXpert to isolate and detect nucleic acid from Bacillus anthracis Ames spores was assessed. METHODS AND RESULTS: A four-plex, dried-down bead cartridge containing PCR reagents specific for the pXO1 and pXO2 plasmids as well as sample processing and inhibition controls was evaluated. For B. anthracis Ames spores harbouring pXO1 and pXO2, samples containing 68 CFU per ml (148 spores per ml) were positive in all four replicates. A limited cross-reactivity panel, which included closely related Bacillus species, was also tested to determine the specificity of the pXO1 and pXO2 assays. No cross-reactivity occurred. Further, B. anthracis Sterne spore samples were analysed to compare results when processed using the GeneXpert to those run directly on the Cepheid SmartCycler without sample processing. The GeneXpert detection capability was three logs lower than the SmartCycler indicating the benefit of incorporating a nucleic acid extraction procedure. CONCLUSIONS: This study demonstrates that the GeneXpert is a rapid and reliable system for simultaneously detecting the B. anthracis virulence plasmids pXO1 and pXO2. SIGNIFICANCE AND IMPACT OF THE STUDY: The GeneXpert is the only platform currently available that is capable of both nucleic acid purification and real-time PCR detection enclosed within a single system. Further, all sample manipulations are automated, thus reducing errors associated with manual processing.
Authors: Peter E Vandeventer; Kris M Weigel; Jose Salazar; Barbara Erwin; Bruce Irvine; Robert Doebler; Ali Nadim; Gerard A Cangelosi; Angelika Niemz Journal: J Clin Microbiol Date: 2011-05-04 Impact factor: 5.948
Authors: Stephen D Lawn; Peter Mwaba; Matthew Bates; Amy Piatek; Heather Alexander; Ben J Marais; Luis E Cuevas; Timothy D McHugh; Lynn Zijenah; Nathan Kapata; Ibrahim Abubakar; Ruth McNerney; Michael Hoelscher; Ziad A Memish; Giovanni Battista Migliori; Peter Kim; Markus Maeurer; Marco Schito; Alimuddin Zumla Journal: Lancet Infect Dis Date: 2013-03-24 Impact factor: 25.071
Authors: Danica Helb; Martin Jones; Elizabeth Story; Catharina Boehme; Ellen Wallace; Ken Ho; JoAnn Kop; Michelle R Owens; Richard Rodgers; Padmapriya Banada; Hassan Safi; Robert Blakemore; N T Ngoc Lan; Edward C Jones-López; Michael Levi; Michele Burday; Irene Ayakaka; Roy D Mugerwa; Bill McMillan; Emily Winn-Deen; Lee Christel; Peter Dailey; Mark D Perkins; David H Persing; David Alland Journal: J Clin Microbiol Date: 2009-10-28 Impact factor: 5.948
Authors: Amanda B Herzog; S Devin McLennan; Alok K Pandey; Charles P Gerba; Charles N Haas; Joan B Rose; Syed A Hashsham Journal: Appl Environ Microbiol Date: 2009-07-31 Impact factor: 4.792