Performance of the G4 Xpert MTB/RIF assay for the detection of Mycobacterium tuberculosis and rifampin resistance: a retrospective case-control study of analytical and clinical samples from high- and low-tuberculosis prevalence settings.

Background: The Xpert MTB/RIF (Xpert) assay is a rapid PCR-based assay for the detection of Mycobacterium tuberculosis complex DNA (MTBc) and mutations associated with rifampin resistance (RIF). An updated version introduced in 2011, the G4 Xpert, included modifications to probe B and updated analytic software.

Methods: An analytical study was performed to assess Xpert detection of mutations associated with rifampin resistance in rifampin-susceptible and -resistant isolates.

Rapid detection and differentiation of human noroviruses using RT-PCR coupled to electrospray ionization mass spectrometry.

The goal of this study was to develop an assay for the detection and differentiation of noroviruses using RT-PCR followed by electrospray ionization mass spectrometry (ESI-MS). Detection of hepatitis A virus was also considered. Thirteen primer pairs were designed for use in this assay and a reference database was created using GenBank sequences and reference norovirus samples.