False-positive rifampin resistant results with Xpert MTB/RIF version 4 assay in clinical samples with a low bacterial load

Diagn Microbiol Infect Dis. 2016 May;85(1):53-5. doi: 10.1016/j.diagmicrobio.2016.01.009. Epub 2016 Jan 15.

Abstract

We report investigation of 22 TB cases with positive Xpert MTB/RIF result for resistance to Rifampin and "Very Low" MTB detection level. Twelve cases were false positive without rpoB mutations, 2 were false-positives with a silent mutation in rpoB codon T508, and only 10 were true positives.

Keywords: Developing and high-burden countries; MDR-TB; Molecular diagnostics; Tuberculosis; Xpert MTB/RIF.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Bacterial Load*
  • Humans
  • Microbial Sensitivity Tests*
  • Mutation
  • Mycobacterium tuberculosis / drug effects*
  • Mycobacterium tuberculosis / genetics*
  • Real-Time Polymerase Chain Reaction*
  • Reproducibility of Results
  • Rifampin / pharmacology*
  • Sputum / microbiology
  • Tuberculosis, Multidrug-Resistant / diagnosis*
  • Tuberculosis, Multidrug-Resistant / microbiology*
  • Tuberculosis, Pulmonary / diagnosis
  • Tuberculosis, Pulmonary / microbiology

Substances

  • Rifampin