Tuberculosis ethambutol resistance: concordance between phenotypic and genotypic test results

Hdl Handle:
http://hdl.handle.net/10144/132830
Title:
Tuberculosis ethambutol resistance: concordance between phenotypic and genotypic test results
Authors:
Plinke, Claudia; Cox, Helen S; Kalon, Stobdan; Doshetov, Daribay; Rüsch-Gerdes, Sabine; Niemann, Stefan
Journal:
Tuberculosis (Edinburgh, Scotland)
Abstract:
embB306 mutations are potential markers for detecting ethambutol resistance in clinical Mycobacterium tuberculosis isolates. However, more recently, embB306 mutations have been found in ethambutol susceptible isolates and an association with broad drug resistance rather than ethambutol resistance has been reported. To further investigate this question, we analyzed the association between embB306 mutations and phenotypic ethambutol resistance among 197 isolates from a drug resistance survey performed in Karakalpakstan, Uzbekistan. 39 strains had an embB306 mutation, out of which seven were ethambutol susceptible, thus, displaying discrepant test results. After re-analysis, the seven isolates were tested ethambutol resistant. All of these strains had an increased ethambutol MIC, however, three strains showed no or weak growth on the critical concentration of 2 microg/ml on Löwenstein-Jensen. In three strains we confirmed the presence of heteroresistant mixed populations which might influence conventional ethambutol testing. Final concordance between molecular and phenotypic EMB testing was high with a sensitivity of 78% and a specificity of 100%. Our results confirm that embB306 mutations are useful markers for predicting ethambutol resistance. Discrepancies between molecular and phenotypic ethambutol resistance test results are most likely caused by problems with conventional susceptibility testing.
Affiliation:
Molecular Mycobacteriology, Research Center Borstel, Borstel, Germany; Macfarlane Burnet Institute for Medical Research and Public Health, Australia; Me´decins Sans Frontie`res, Uzbekistan; Ministry of Health, Karakalpakstan, Uzbekistan; National Reference Center for Mycobacteria, Research Center Borstel, Borstel, Germany
Issue Date:
2-Oct-2009
URI:
http://hdl.handle.net/10144/132830
DOI:
10.1016/j.tube.2009.09.001
PubMed ID:
19800845
Additional Links:
http://www.tuberculosisjournal.com/article/S1472-9792(09)00083-3/abstract
Type:
Article
Language:
en
ISSN:
1873-281X
Appears in Collections:
TB

Full metadata record

DC FieldValue Language
dc.contributor.authorPlinke, Claudiaen
dc.contributor.authorCox, Helen Sen
dc.contributor.authorKalon, Stobdanen
dc.contributor.authorDoshetov, Daribayen
dc.contributor.authorRüsch-Gerdes, Sabineen
dc.contributor.authorNiemann, Stefanen
dc.date.accessioned2011-06-08T23:45:14Z-
dc.date.available2011-06-08T23:45:14Z-
dc.date.issued2009-10-02-
dc.identifier.citationTuberculosis (Edinb) 2009;89(6):448-52en
dc.identifier.issn1873-281X-
dc.identifier.pmid19800845-
dc.identifier.doi10.1016/j.tube.2009.09.001-
dc.identifier.urihttp://hdl.handle.net/10144/132830-
dc.description.abstractembB306 mutations are potential markers for detecting ethambutol resistance in clinical Mycobacterium tuberculosis isolates. However, more recently, embB306 mutations have been found in ethambutol susceptible isolates and an association with broad drug resistance rather than ethambutol resistance has been reported. To further investigate this question, we analyzed the association between embB306 mutations and phenotypic ethambutol resistance among 197 isolates from a drug resistance survey performed in Karakalpakstan, Uzbekistan. 39 strains had an embB306 mutation, out of which seven were ethambutol susceptible, thus, displaying discrepant test results. After re-analysis, the seven isolates were tested ethambutol resistant. All of these strains had an increased ethambutol MIC, however, three strains showed no or weak growth on the critical concentration of 2 microg/ml on Löwenstein-Jensen. In three strains we confirmed the presence of heteroresistant mixed populations which might influence conventional ethambutol testing. Final concordance between molecular and phenotypic EMB testing was high with a sensitivity of 78% and a specificity of 100%. Our results confirm that embB306 mutations are useful markers for predicting ethambutol resistance. Discrepancies between molecular and phenotypic ethambutol resistance test results are most likely caused by problems with conventional susceptibility testing.en
dc.language.isoenen
dc.relation.urlhttp://www.tuberculosisjournal.com/article/S1472-9792(09)00083-3/abstracten
dc.rightsArchived with thanks and permission from Elsevier and Tuberculosis (Edinburgh, Scotland)en
dc.subject.meshTuberculosisen
dc.subject.meshethambutol resistanceen
dc.subject.meshUzbekistanen
dc.titleTuberculosis ethambutol resistance: concordance between phenotypic and genotypic test resultsen
dc.typeArticleen
dc.contributor.departmentMolecular Mycobacteriology, Research Center Borstel, Borstel, Germany; Macfarlane Burnet Institute for Medical Research and Public Health, Australia; Me´decins Sans Frontie`res, Uzbekistan; Ministry of Health, Karakalpakstan, Uzbekistan; National Reference Center for Mycobacteria, Research Center Borstel, Borstel, Germanyen
dc.identifier.journalTuberculosis (Edinburgh, Scotland)en

Related articles on PubMed

All Items in MSF are protected by copyright, with all rights reserved, unless otherwise indicated.