On Improving Chemotherapy Outcomes in Patients with Drug-Resistant Tuberculosis as a Result of Introduction of Drug Susceptibility Testing

The objective: to evaluate the effectiveness of chemotherapy in patients with extrapulmonary tuberculosis (EPTB) after introduction of molecular genetic and phenotypic rapid methods for drug susceptibility testing. Subjects and Methods. From 2018 to 2021, epidemiological surveillance forms for drug-resistant tuberculosis (DR TB) (TB 06, Table 3b for Results of Drug Susceptibility Testing to First- and Second-Line Drugs) were analyzed. Those forms were approved by the Ministry of Health of the Kyrgyz Republic (KR) in 2014. During this period, molecular genetic tests (GeneXpert/MTB-Rif, LPA, MTBDRsl) began to be used for testing drug susceptibility of Mycobacterium tuberculosis (MTB), while the use of phenotypic tests (cultures on liquid (MGIT 960) media and solid media (Levenshtein-Jensen (LJ)) continued. Results. In the Kyrgyz Republic, over 4 years (2018 - 2021), the proportion of MTB strains sensitive to anti-tuberculosis drugs was growing from 44.0% in 2018 to 58.9% in 2021. Among the drug-resistant MTB strains, the proportion of isoniazid-resistant ones increased from 18.9% to 28.7%. In 2020 and 2021, the treatment effectiveness of patients with drug-susceptible extrapulmonary tuberculosis made 84.8 and 83.9%, respectively, and almost reached the target rate of 85% of the National Tuberculosis Control Program of the Kyrgyz Republic. In Bishkek in 2018, the treatment effectiveness in patients with DR extrapulmonary tuberculosis was close to the target of the National Program (75%) and amounted to 73.5%, and in 2019 it exceeded the target rate and reached 82.4%.