Comprehensive Quality Assurance Intervention for Reliable Drug Susceptibility Testing Results for TB in Armenia
S Andres(1) I Friesen(1) E Kabasakalyan(5) N Shubladze(6) C U Köser(2) L de Araujo(3) C Utpatel(3) I Barilar(3) A Yedilbayev(4) S Niemann(1,3) S Ehsani(4)
1:National and World Health Organization Supranational Reference Laboratory for Mycobacteria, Research Center Borstel, Leibniz Lung Center, Borstel, 23845, Germany; 2:Department of Genetics, University of Cambridge, Cambridge, Downing Street, Cambridge CB2 3EH, UK.; 3:Molecular Mycobacteriology, Research Center Borstel - Leibniz Lung Center, Borstel, 23845, Germany; 4:World Health Organization, Regional Office for Europe, Joint Infectious Diseases Programme, Marmorvej 51, 2100 Copenhagen, Denmark; 5:National TB Reference Laboratory, National Center of Pulmonology SNCO, MH, Armenia; 6:WHO-EURO laboratory consultant, National Center for TB and Lung Diseases of Georgia
Drug susceptibility testing (DST) is a critical component of tuberculosis (TB) control by allowing clinicians to select effective treatment regimens, thereby minimising the selection and transmission of drug resistance (DR). With estimated new and previously treated TB cases with DR-TB, which is 19% and 48% respectively and smaller number of lab-confirmed cases in 2021, DR-TB remains a public health concern in Armenia. To ensure the quality and reliability of DST results in Armenia, we conducted a comprehensive quality assurance (QA) intervention plan.
59 presumed MDR Mycobacterium tuberculosis complex (Mtbc) strains isolated in Armenia in 2022 were tested by routine genotypic and phenotypic DST (g/pDST) at the Armenian reference laboratory. Results were complemented with pDST and whole-genome sequencing (WGS) based resistance prediction at the Supranational Reference Laboratory in Borstel, Germany.
High concordance between the pDST results of the two NRLs was observed for isoniazid (H), rifampicin (R), moxifloxacin (Mfx), bedaquiline (BDQ), linezolid (Lzd), clofazimine (CFZ), Ethambutol (E) and delamanid (Dlm). All borderline rpoB mutations were detected by Xpert. The WGS result were crucial to interpret the pDST results for E, pyrazinamide (Z), BDQ and CFZ.
Results of WGS allowed to assess the accuracy of pDST to E, Z, BDQ and CFZ. Quality-assured DST results and a strategy to implement all recommended genotypic methods in countries with growing MDR rates should be prioritized. Overall, the need for additional, comprehensive and standardized, QA assessments was demonstrated to complement the annual WHO external quality assessment.