1363. Does Genotypic Testing Improve Treatment Outcomes in Drug-Resistant Tuberculosis?

Abstract

BackgroundTreatment of drug-resistant tuberculosis (DR-TB) requires toxic and complex drug regimens. Dismal outcomes occur due to a delay in the report of susceptibility results. WHO endorses genotypic tests like line probe assay (Mtbdrsl) for an early diagnosis enabling start of robust treatment regimens. Data correlating Mtbdrsl and specific mutations with outcome are rare.MethodsA concurrent cohort study was conducted on all patients diagnosed to have DR-TB between January 2016 and June 2017 in the departments of Pulmonary Medicine and Infectious Diseases at a tertiary care center in India. Patients aged >18 years with a positive Mtbdrsl (done on culture) or Mycobacterial culture were prospectively followed up till completion of therapy for assessment of outcomes. Patients were divided into 2 groups based on diagnostic method used: culture group and Mtbdrsl group. Risk factors for adverse outcomes were assessed.ResultsTotal of 82 patients, of which 62.2% were males with a mean age of 32 years were included; 50 in the Mtbdrsl group and 32 in the culture group. Among these, 40.2% were multi-drug-resistant Tuberculosis (MDR-TB), 53.7% were Pre–XDR (pre-extensively drug resistant i.e, quinolone-resistant tuberculosis) and 6.1% were XDR (extensively drug-resistant TB). Isolated pulmonary involvement (46.3%) was common followed by disseminated TB (29.3%). Overall good outcome was seen in 39/82 (14.6% cured and 32.9% completed treatment) and bad outcome in 43/82 (41.5% lost to follow up, 7.3% treatment failure and 3.7% died). Good outcome was noted in Mtbdrsl group was 22/50 (44%) vs. 17/32 (53.1%) in the culture group. Mtbdrsl group had 140 days mean decrease in time to initiation of appropriate therapy but the odds of having a better outcome was 0.693 (CI: 0.284–1.690, P = 0.499). Among the 15 different types of mutations, FQ mutations gyrA 94Gly and gyrA 90Val comprised 15% each with gyrA 94Gly noted to have a poorer outcome [OR 2.5 (CI 0.471–13.265)]. All 5 patients with XDR TB (50 % had rrs 1401Gly mutation) had a poor outcome.ConclusionContrary to what is expected, Mtbdrsl did not significantly contribute to better treatment outcomes. High-risk mutation gyrA 94Gly was prevalent and associated with poorer outcomes. Small sample size and a wide variety of mutations preclude generalizability of our results.Disclosures All authors: No reported disclosures.