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Correlation of different phenotypic drug susceptibility testing methods for four fluoroquinolones in Mycobacterium tuberculosis

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Show simple item record Coeck, N. de Jong, B. C. Diels, M. De Rijk, P. Ardizzoni, E. Van Deun, A. Rigouts, L. 2016-05-25T14:36:06Z 2016-05-25T14:36:06Z 2016
dc.identifier.issn 0305-7453
dc.identifier.other ITG-B1B
dc.identifier.other ITG-B2A
dc.identifier.other ITG-B3B
dc.identifier.other ITG-B4B
dc.identifier.other ITG-B5B
dc.identifier.other ITG-B6A
dc.identifier.other ITG-BLA
dc.identifier.other DBM
dc.identifier.other U-MYCOB
dc.identifier.other JIF
dc.identifier.other DOI
dc.identifier.other FTA
dc.identifier.other OAA
dc.identifier.other Abstract
dc.identifier.other UPD62
dc.description.abstract BACKGROUND: Molecular resistance testing fails to explain all fluoroquinolone resistance, with a continued need for a suitable rapid phenotypic drug susceptibility testing method. OBJECTIVE: To evaluate the optimal method for phenotypic fluoroquinolone susceptibility testing. METHODS: Using Lowenstein-Jensen medium, Middlebrook 7H11 agar, BACTEC-MGIT 960 and the resazurin microtitre plate assay, we determined susceptibility to fluoroquinolones in Mycobacterium tuberculosis and investigated cross-resistance between ofloxacin, levofloxacin, moxifloxacin and gatifloxacin. We compared MICs of all four fluoroquinolones for 91 strains on Lowenstein-Jensen (as the gold standard) with their MICs in resazurin plates, and with ofloxacin susceptibility at a single concentration in MGIT and on 7H11 agar, in addition to sequencing of the gyrAB genes. RESULTS AND CONCLUSIONS: Applying a cut-off of 2 mg/L ofloxacin, 1 mg/L levofloxacin and 0.5 mg/L moxifloxacin and gatifloxacin in all methods, some discordance between solid medium and MGIT methods was observed, yet this tended to be explained by MICs around the cut-off. The high discordance between Lowenstein-Jensen (LJ) and resazurin plates suggests that the currently applied cut-offs for all fluoroquinolones in the resazurin method should decrease and minor changes in colour (from blue to purple) be considered as meaningful. High-level resistance in all assays to all drugs correlated well with the presence of gyrA mutations, in support of recent findings that fluoroquinolone resistance should be tested at different concentrations, as patients with lower levels of resistance may continue to benefit from high-dose fluoroquinolone-based therapy. en_US
dc.language English en_US
dc.subject Bacterial diseases en_US
dc.subject Tuberculosis en_US
dc.subject Mycobacterium tuberculosis en_US
dc.subject Drug susceptibility en_US
dc.subject Testing en_US
dc.subject Phenotyping en_US
dc.subject Methodology en_US
dc.subject Fluoroquinolones en_US
dc.subject Performance en_US
dc.subject Comparison en_US
dc.subject Löwenstein-Jensen en_US
dc.subject Middlebrook 7H11 en_US
dc.subject BACTEC en_US
dc.subject Resazurin en_US
dc.subject Laboratory techniques and procedures en_US
dc.title Correlation of different phenotypic drug susceptibility testing methods for four fluoroquinolones in Mycobacterium tuberculosis en_US
dc.type Article en_US
dc.citation.issue 5 en_US
dc.citation.jtitle Journal of Antimicrobial Chemotherapy en_US
dc.citation.volume 71 en_US
dc.citation.pages 1233-1240 en_US
dc.citation.jabbreviation J Antimicrob Chemother en_US

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