Retrospective Analysis of False-Positive and Disputed Rifampin Resistance Xpert MTB/RIF Assay Results in Clinical Samples from a Referral Hospital in Hunan, China.
J Clin Microbiol
; 57(4)2019 04.
Article
in En
| MEDLINE
| ID: mdl-30674578
ABSTRACT
Concerns about the specificity of the Xpert MTB/RIF (Xpert) assay have arisen, as false-positive errors in the determination of Mycobacterium tuberculosis complex (MTBC) infection and rifampin (RIF) resistance in clinical practice have been reported. Here, we investigated 33 cases where patients were determined to be RIF susceptible using the Bactec MGIT 960 (MGIT) culture system but RIF resistant using the Xpert assay. Isolates from two of these patients were found not to have any mutations in the rifampin resistance determining region (RRDR) region of rpoB and had good treatment outcomes with first-line antituberculosis (anti-TB) drugs. The remaining 31 patients included 5 new cases and 26 previously treated patients. A large number of well-documented disputed mutations, including Leu511Pro, Asp516Tyr, His526Asn, His526Leu, His526Cys, and Leu533Pro, were detected, and mutations, including a 508 to 509 deletion and His526Gly, were described here as disputed mutations for the first time. Twenty-one (81%) of the 26 previously treated patients had poor treatment outcomes, and isolates from 19 (90%) of these 21 patients were resistant to isoniazid (INH) as determined using the MGIT culture system. Twenty-seven of the 31 isolates with disputed rpoB mutations were phenotypically resistant to INH, 21 (78%) being predicted by GenoType MTBDRplus to have a high level of INH resistance. Most (77.4%) of the isolates with disputed mutations were of the Beijing lineage. These findings have implications for the interpretation of false-positive and disputed rifampin resistance Xpert MTB/RIF results in clinical samples and provide guidance on how clinicians should manage patients carrying isolates with disputed rpoB mutations.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Rifampin
/
Tuberculosis
/
Molecular Diagnostic Techniques
/
Mycobacterium tuberculosis
/
Antitubercular Agents
Type of study:
Diagnostic_studies
/
Guideline
/
Observational_studies
/
Prognostic_studies
/
Risk_factors_studies
Limits:
Adolescent
/
Adult
/
Aged
/
Female
/
Humans
/
Male
/
Middle aged
Country/Region as subject:
Asia
Language:
En
Journal:
J Clin Microbiol
Year:
2019
Document type:
Article
Affiliation country:
China
Publication country:
EEUU
/
ESTADOS UNIDOS
/
ESTADOS UNIDOS DA AMERICA
/
EUA
/
UNITED STATES
/
UNITED STATES OF AMERICA
/
US
/
USA