gms | German Medical Science

10. Kongress für Infektionskrankheiten und Tropenmedizin (KIT 2010)

Deutsche Gesellschaft für Infektiologie,
Deutsche AIDS-Gesellschaft,
Deutsche Gesellschaft für Tropenmedizin und Internationale Gesundheit,
Paul-Ehrlich-Gesellschaft für Chemotherapie

23.06. - 26.06.2010, Köln

Detection of Mycobacterium tuberculosis using the Cepheid Xpert MTB/RIF® Assay – a clinical validation study from Tanzania

Nachweis von Mycobacterium tuberculosis mittels des Cepheid GeneXpert MBT/RIF® Assays – eine klinische Validierungsstudie aus Tansania

Meeting Abstract

  • A. Rachow - University of Munich, Dept. for Infectious Diseases and Tropical Medicine, Munich, Germany; NIMR-Mbeya Medical Research Programme, Mbeya, Tanzania
  • G. Rojas-Ponce - NIMR-Mbeya Medical Research Programme, Mbeya, Tanzania
  • E. Saathoff - University of Munich, Dept. for Infectious Diseases and Tropical Medicine, Munich, Germany
  • K. Reither - University of Munich, Dept. for Infectious Diseases and Tropical Medicine, Munich, Germany; NIMR-Mbeya Medical Research Programme, Mbeya, Tanzania
  • C. Boehme - Foundation for Innovative New Diagnostics (FIND), Geneva, Switzerland
  • M. Perkins - Foundation for Innovative New Diagnostics (FIND), Geneva, Switzerland
  • M. Hoelscher - University of Munich, Dept. for Infectious Diseases and Tropical Medicine, Munich, Germany
  • N. Heinrich - University of Munich, Dept. for Infectious Diseases and Tropical Medicine, Munich, Germany

10. Kongress für Infektionskrankheiten und Tropenmedizin (KIT 2010). Köln, 23.-26.06.2010. Düsseldorf: German Medical Science GMS Publishing House; 2010. DocTRO 04-5

DOI: 10.3205/10kit055, URN: urn:nbn:de:0183-10kit0554

Veröffentlicht: 2. Juni 2010

© 2010 Rachow et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielfältigt, verbreitet und öffentlich zugänglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

Background: Tuberculosis (TB) control is hampered by inadequate diagnosis, especially in resource-poor countries. New, rapid and simple-to-use diagnostic tools are desperately needed. Here we evaluate the Xpert MTB/RIF® test (Cepheid, USA), a cartridge-based real-time PCR assay that automates sample processing, amplification, detection of M. tuberculosis and resistance to rifampicin.

Methods: 292 consecutively enrolled patients were classified as TB positive or negative following results of sputum smear, solid or liquid culture on three different sputa and resolution of symptoms on follow-up one and two months after initial assessment. The Xpert MTB/RIF® test (Xpert) was performed on two frozen, untreated sputum samples per patient.

Results: Of 69 culture-positive (LJ and/or MGIT) TB cases, 88.4% were detected by Xpert (95% CI=78–95%). There was a marked difference in sensitivity between smear-positive and only culture-positive patients, with sensitivities of 100% and 62% (95% CI=38–82%) respectively. In accordance with susceptibility testing in liquid culture, no rifampicin resistance was detected by Xpert. Among all TB negative patients, Xpert detected one positive result (99% specificity). One of the samples from 45 patients that were culture-positive for non-tuberculous mycobacteria (NTM) was tested positive by Xpert. Additional analysis is underway to elucidate on these results.

Conclusion: This study evaluates the Xpert in a cohort of consecutively enrolled TB-suspected patients and simulates a typical clinical setting. We demonstrated that the utilization of the Xpert can increase the number of microbiologically identified patients significantly, compared to microscopy, the standard diagnostic procedure in most developing countries. With its easy-to-use technology, Xpert has the potential to play an important role in combating the TB epidemic. Further studies are needed to confirm its performance on fresh sputum samples and on other clinical material.