S125 Isoniazid resistant tuberculosis(Hr-TB): a problem well stated is a problem half solved!

<h3>Background</h3> Isoniazid (INH) is an important first line drug in the management of active and latent TB. Its widespread use and lack of diagnostic testing has resulted in an increase in the prevalence of Hr-TB, either alone or in combination with other drugs. katG and inhA mutations confer high and low level INH resistance respectively. <h3>Methods</h3> Patients with Hr-TB were enrolled in a prospective observational cohort at a public tertiary care hospital in India. Demographic characteristics, clinico-microbiological profile and treatment outcomes were noted (table 1). Samples were analyzed using line probe assays (LPA). Treatment and defined outcomes were as per national program guidelines. <h3>Results</h3> 442 patients were included. It was a young cohort with male predominance (n=287,64.9%). 89 (20.1%) subjects had presumptive TB whereas 23 (5.2%) were previously treated for TB. 1.4% of subjects had HIV coinfection and 10.2% were diabetic. Sputum samples were most commonly tested (n=309,69.9%) followed by lymph nodes (n=107,29.2%). (n=63,14.3%) subjects had a negative AFB smear despite a positive LPA. (n=207,69%) patients had katG mutation whereas (n=88, 29.3%) had inhA mutation on I line LPA. 43 (9.7%) patients had additional drug resistance on II line LPA (8.1% with fluoroquinolones(FQ), 0.9% with second line injectables(SLI) and 0.7% with both FQ &amp; SLI). (n=306,69.3%) were declared cured and (n=32 7.3%) died. Outcomes were significantly worse in males (p=0.04) and with additional drug resistance (p=0.03). Age, mutation type, comorbidities did not affect treatment outcomes. <h3>Conclusion</h3> Hr-TB is frequently underdiagnosed and mismanaged leading to acquired drug resistance. LPA and universal DST should form an integral part of the TB program.