Comparison of line probe assay to BACTEC MGIT 960 system for susceptibility testing of first and second-line anti-tuberculosis drugs in a referral laboratory in South Africa

BMC Infectious Diseases

Research Article

Nontuthuko E. Maningi¹  John F. Antiabong¹  Nontombi M. Mbelle²  Ruth M. Lekalakala³  Lesibana A. Malinga⁴ 

[1] Department of Medical Microbiology, Faculty of Health Sciences, University of Pretoria, Private Bag X323, 0007, Arcadia, South Africa;Department of Medical Microbiology, Faculty of Health Sciences, University of Pretoria, Private Bag X323, 0007, Arcadia, South Africa;Tshwane Division, National Health Laboratory Services, Pretoria, South Africa;Tshwane Division, National Health Laboratory Services, Pretoria, South Africa;Tuberculosis Platform, South African Medical Research Council, Pretoria, South Africa;

关键词: Drug-resistance;    Mycobacterium tuberculosis;    Line-probe assay;    MGIT 960 system;    Isoniazid;    Rifampicin;    Ethambutol;    Ofloxacin;    Kanamycin;   

DOI  :  10.1186/s12879-017-2898-3

 received in 2017-02-13, accepted in 2017-12-10,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundThe incidence of multidrug-resistant tuberculosis (MDR-TB) is increasing and the emergence of extensively drug-resistant tuberculosis (XDR-TB) is a major challenge. Controlling resistance, reducing transmission and improving treatment outcomes in MDR/XDR-TB patients is reliant on susceptibility testing. Susceptibility testing using phenotypic methods is labour intensive and time-consuming. Alternative methods, such as molecular assays are easier to perform and have a rapid turn-around time. The World Health Organization (WHO) has endorsed the use of line probe assays (LPAs) for first and second line diagnostic screening of MDR/XDR-TB.MethodsWe compared the performance of LPAs to BACTEC MGIT 960 system for susceptibility testing of bacterial resistance to first-line drugs: rifampicin (RIF), isoniazid (INH), ethambutol (EMB), and second-line drugs ofloxacin (OFL) and kanamycin (KAN). One hundred (100) consecutive non-repeat Mycobacterium tuberculosis cultures, resistant to either INH or RIF or both, as identified by BACTEC MGIT 960 were tested. All isoniazid resistant cultures (n = 97) and RIF resistant cultures (n = 90) were processed with Genotype®MTBDRplus and Genotype®MTBDRsl line probe assays (LPAs). The agar proportion method was employed to further analyze discordant LPAs and the MGIT 960 isolates.ResultsThe Genotype ®MTBDRplus (version 2) sensitivity, specificity, PPV and NPV from culture isolates were as follows: RIF, 100%, 87.9, 58.3% and 100%; INH, 100%, 94.4%, 93.5% and 100%. The sensitivity, specificity PPV and NPV for Genotype ® MTBDRsl (version 1 and 2) from culture isolates were as follows: EMB, 60.0%, 89.2%, 68.2% and 85.3%; OFL, 100%, 91.4%, 56.2% and 100%; KAN, 100%, 97.7%, 60.0% and 100%. Line probe assay showed an excellent agreement (k = 0.93) for INH susceptibility testing when compared to MGIT 960 system while there was good agreement (k = 0.6–0.7) between both methods for RIF, OFL, KAN testing and moderate agreement for EMB (k = 0.5). A high RIF mono-resistance (MGIT 960 33/97 and LPA 43/97) was observed.ConclusionLPAs are an efficient and reliable rapid molecular DST assay for rapid susceptibility screening of MDR and XDR-TB. Using LPAs in high MDR/XDR burden countries allows for appropriate and timely treatment, which will reduce transmission rates, morbidity and improve treatment outcomes in patients.

【 授权许可】

CC BY   
© The Author(s). 2017