The potential utility of Xpert® MTB/RIF for real-time surveillance of drug resistance in rural KwaZulu-Natal, South Africa
The potential utility of Xpert® MTB/RIF for real-time surveillance of drug resistance in rural KwaZulu-Natal, South Africa
Background:
The Xpert® MTB/RIF system is a molecular diagnostic for the detection of Mycobacterium tuberculosis and rifampicin resistance. Linkage of basic clinical information to the laboratory system could enhance real-time surveillance of drug resistance at a population level.
Methods:
A cluster randomised trial comparing two Xpert® MTB/RIF positioning strategies for adult pulmonary TB suspects. This preliminary analysis uses individual-level data across the trial arms combined from the first 30 weeks of enrolment and focuses on prevalence of rifampicin resistance in specific groups of suspects (current TB/previous TB/no previous TB). Current TB group includes participants suspected of MDR-TB (smear non-conversion or treatment failure on a standard TB treatment regimen).
Results:
558 submitted sputum specimens; 546 (98%) with valid Xpert® MTB/RIF result. Sensitivity and specificity for detection of multidrug resistance (against reference of line probe assay on culture isolate) were respectively 83.3% (95%CI 36.5–99.1) and 100% (95%CI 88.3–100). The Xpert® MTB/RIF results for the three groups are displayed in the table. Rifampicin resistance was defined most commonly by probes E (58%) and B (33%).
Conclusions and recommendations:
The detection of rifampicin resistance by the Xpert® MTB/RIF assay is a reliable indicator of multidrug resistance in this high burden setting. As expected, the prevalence of rifampicin resistance is higher among previously treated cases than among those not previously treated. As implementation is scaled up, incorporation of basic clinical data into Xpert® MTB/RIF laboratory systems could enhance the utility of this molecular diagnostic tool for real-time surveillance of drug resistance at a population level.
Lessells, R.J.
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Cooke, G.S.
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Nicol, M.P.
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McGrath, N.
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de Oliveira, T.
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Newell, M.L.
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Godfrey-Faussett, P.
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16 November 2012
Lessells, R.J.
54b2808f-a135-46ea-92df-ad2e6512dbf8
Cooke, G.S.
3f8fc4b7-d143-47e4-832b-0cfb9b1058f1
Nicol, M.P.
97abfb6e-5d98-466a-af96-4a4c9ccfd570
McGrath, N.
b75c0232-24ec-443f-93a9-69e9e12dc961
de Oliveira, T.
c657f813-01c5-4700-bc81-f34b163b8003
Newell, M.L.
c6ff99dd-c23b-4fef-a846-a221fe2522b3
Godfrey-Faussett, P.
5c1047a6-ac3f-45ed-81c8-4549cd652caa
Lessells, R.J., Cooke, G.S., Nicol, M.P., McGrath, N., de Oliveira, T., Newell, M.L. and Godfrey-Faussett, P.
(2012)
The potential utility of Xpert® MTB/RIF for real-time surveillance of drug resistance in rural KwaZulu-Natal, South Africa.
43rd World Conference on Lung Health of the International Union against Tuberculosis and Lung Disease, Kuala Lumpur, Malaysia.
13 - 17 Nov 2012.
Record type:
Conference or Workshop Item
(Paper)
Abstract
Background:
The Xpert® MTB/RIF system is a molecular diagnostic for the detection of Mycobacterium tuberculosis and rifampicin resistance. Linkage of basic clinical information to the laboratory system could enhance real-time surveillance of drug resistance at a population level.
Methods:
A cluster randomised trial comparing two Xpert® MTB/RIF positioning strategies for adult pulmonary TB suspects. This preliminary analysis uses individual-level data across the trial arms combined from the first 30 weeks of enrolment and focuses on prevalence of rifampicin resistance in specific groups of suspects (current TB/previous TB/no previous TB). Current TB group includes participants suspected of MDR-TB (smear non-conversion or treatment failure on a standard TB treatment regimen).
Results:
558 submitted sputum specimens; 546 (98%) with valid Xpert® MTB/RIF result. Sensitivity and specificity for detection of multidrug resistance (against reference of line probe assay on culture isolate) were respectively 83.3% (95%CI 36.5–99.1) and 100% (95%CI 88.3–100). The Xpert® MTB/RIF results for the three groups are displayed in the table. Rifampicin resistance was defined most commonly by probes E (58%) and B (33%).
Conclusions and recommendations:
The detection of rifampicin resistance by the Xpert® MTB/RIF assay is a reliable indicator of multidrug resistance in this high burden setting. As expected, the prevalence of rifampicin resistance is higher among previously treated cases than among those not previously treated. As implementation is scaled up, incorporation of basic clinical data into Xpert® MTB/RIF laboratory systems could enhance the utility of this molecular diagnostic tool for real-time surveillance of drug resistance at a population level.
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More information
Published date: 16 November 2012
Venue - Dates:
43rd World Conference on Lung Health of the International Union against Tuberculosis and Lung Disease, Kuala Lumpur, Malaysia, 2012-11-13 - 2012-11-17
Organisations:
Primary Care & Population Sciences, Faculty of Social, Human and Mathematical Sciences
Identifiers
Local EPrints ID: 350634
URI: http://eprints.soton.ac.uk/id/eprint/350634
PURE UUID: 701c77e5-14a9-46ff-b16c-2e19014e70ea
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Date deposited: 27 Mar 2013 14:51
Last modified: 23 Jul 2022 02:07
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Contributors
Author:
R.J. Lessells
Author:
G.S. Cooke
Author:
M.P. Nicol
Author:
T. de Oliveira
Author:
P. Godfrey-Faussett
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