Can a simple flotation method lower the limit of detection of Mycobacterium tuberculosis in extrapulmonary samples analyzed by the GeneXpert MTB/RIF assay?

Journal of Clinical Microbiology
Nathan TaylorNiaz Banaei

Abstract

The rapid and accurate diagnosis of tuberculosis (TB) in children and extrapulmonary TB in adults continues to be a challenge. In this study, we determined the lower limit of detection (LOD) of the GeneXpert MTB/RIF assay with nonrespiratory specimens and investigated the utility of flotation procedures for concentrating the bacilli. Clinical specimens (9 cerebrospinal fluid [CSF], 13 gastric aspirate, 8 tissue, and 17 stool) were spiked with single-celled Mycobacterium tuberculosis, and the LOD of the GeneXpert assay was determined. Flotation studies were conducted with sucrose and NaCl, and the cycle thresholds of the MTB/RIF assay were compared between treated and untreated samples. There was no significant difference between the LODs of the GeneXpert assay with saline solution (median, 33 CFU/ml) and CSF (median, 25 CFU/ml) (P > 0.05) or gastric aspirate samples (median, 58 CFU/ml) (P > 0.05). The LOD with spiked tissue (median, 1,525 CFU/ml) and stool samples (median, 6,800 CFU/ml) was significantly elevated compared to that determined with saline solution (P ≤ 0.05 and ≤ 0.0005, respectively). Flotation studies with sucrose or NaCl did not consistently result in lowered cycle thresholds in stool or gastric aspirates, but ...Continue Reading

References

Dec 1, 1992·Journal of Clinical Microbiology·M N WidjojoatmodjoJ Verhoef
Jul 2, 1999·Applied and Environmental Microbiology·E Kuczynska, D R Shelton
May 28, 2010·Journal of Clinical Microbiology·Robert BlakemoreDavid Alland
Sep 10, 2010·The New England Journal of Medicine·Catharina C BoehmeMark D Perkins
Jan 29, 2011·Journal of Clinical Microbiology·Doris HillemannElvira Richter
Mar 15, 2011·The International Journal of Tuberculosis and Lung Disease : the Official Journal of the International Union Against Tuberculosis and Lung Disease·B MalbrunyV Cattoir
May 20, 2011·Journal of Clinical Microbiology·Viral VadwaiCamilla Rodrigues
Jun 10, 2011·Journal of Clinical Microbiology·Manuel CausseManuel Casal
Dec 16, 2011·Lab on a Chip·Peng GuoRichard N Zare

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Citations

Jan 23, 2014·The Cochrane Database of Systematic Reviews·Karen R SteingartNandini Dendukuri
Apr 26, 2018·The American Journal of Tropical Medicine and Hygiene·Andrew R DiNardoAnna M Mandalakas
Feb 6, 2017·The Pediatric Infectious Disease Journal·Elisabetta WaltersAnneke C Hesseling
May 6, 2015·Expert Review of Anti-infective Therapy·Elisabetta VenturiniElena Chiappini
Jun 8, 2019·The Cochrane Database of Systematic Reviews·David J HorneKaren R Steingart

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