title: False-positive rifampicin resistance on Xpert® MTB/RIF caused by a silent mutation in the rpoB gene.
abstract: The Xpert® MTB/RIF assay detects the presence of Mycobacterium tuberculosis and its resistance to rifampicin (RMP) directly in sputum samples. Discrepant results were observed in a case of smear-positive pulmonary tuberculosis that was Xpert-resistant but phenotypically susceptible to RMP. Complementary investigations (repeat Xpert, Genotype®MTBDRplus assay and sequencing of the rpoB gene) revealed the presence of a silent mutation in the rpoB gene, leading to the conclusion of a false-positive Xpert result. As misinterpretation of Xpert results may lead to inappropriate treatment, the presence of rpoB mutations should be confirmed by sequencing the rpoB gene.
authors.affiliation: National Reference Centre of Tuberculosis and Mycobacteria, Communicable and Infectious Diseases, Scientific Institute of Public Health, Brussels, Belgium.
authors.forename: V
authors.initials: V
authors.lastname: Mathys
authors.affiliation: Department of Microbiology, Ziekenhuis Netwerk Antwerpen (ZNA) Stuivenberg, Antwerp, Belgium.
authors.forename: M
authors.initials: M
authors.lastname: van de Vyvere
authors.affiliation: Department of Pneumology, ZNA Middelheim, Antwerp, Belgium.
authors.forename: E
authors.initials: E
authors.lastname: de Droogh
authors.affiliation: National Reference Centre of Tuberculosis and Mycobacteria, Communicable and Infectious Diseases, Scientific Institute of Public Health, Brussels, Belgium.
authors.forename: K
authors.initials: K
authors.lastname: Soetaert
authors.affiliation: Belgian Lung and Tuberculosis Association, Brussels, Belgium.
authors.forename: G
authors.initials: G
authors.lastname: Groenen
mesh_terms: D000368:Aged; D000583:Amikacin / Q000627:therapeutic use; D000595:Amino Acid Sequence; D000904:Antibiotics, Antitubercular / Q000627:therapeutic use; D001426:Bacterial Proteins / Q000235:genetics*; D012321:DNA-Directed RNA Polymerases; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004977:Ethambutol / Q000627:therapeutic use; D005000:Ethionamide / Q000627:therapeutic use; D024841:Fluoroquinolones / Q000627:therapeutic use; D005838:Genotype; D006801:Humans; D007538:Isoniazid / Q000627:therapeutic use; D008297:Male; D008969:Molecular Sequence Data; D000077266:Moxifloxacin; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000235:genetics; D010641:Phenotype; D011718:Pyrazinamide / Q000627:therapeutic use; D012293:Rifampin / Q000627:therapeutic use*; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis / Q000188:drug therapy
chemical_list: D000904:Antibiotics, Antitubercular; D001426:Bacterial Proteins; D024841:Fluoroquinolones; C505805:rpoB protein, Mycobacterium tuberculosis; D011718:Pyrazinamide; D000583:Amikacin; D004977:Ethambutol; D012321:DNA-Directed RNA Polymerases; D005000:Ethionamide; D000077266:Moxifloxacin; D007538:Isoniazid; D012293:Rifampin