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Background Isoniazid-resistant, rifampin-susceptible tuberculosis (Hr-TB) is associated with poor treatment outcomes and higher rates of acquisition of further drug resistance during treatment. Due to a lack of widespread diagnostics, Hr-TB is frequently undetected and its epidemiology is incompletely understood. Methods We studied the molecular epidemiology of Hr-TB among all patients diagnosed with culture-positive pulmonary tuberculosis between January 1 and June 30, 2017, at an urban referral tuberculosis clinic in Port-au-Prince, Haiti. Demographic and clinical data were extracted from the electronic medical record. Archived diagnostic Mycobacterium tuberculosis isolates were tested for genotypic and phenotypic isoniazid resistance using the Genotype MTBDR plus assay (Hain, Nehren, Germany) and culture-based testing, respectively. All isoniazid-resistant isolates and a randomly selected subset of isoniazid-susceptible isolates underwent whole-genome sequencing to confirm the presence of mutations associated with isoniazid resistance, to validate use of Genotype MTBDR plus in this population, and to identify potential transmission links between isoniazid-resistant isolates. Results and Conclusions Among 845 patients with culture-positive pulmonary tuberculosis in Haiti, 65 (7.7%) had Hr-TB based on the Genotype MTBDR plus molecular assay. Age < 20 years was significantly associated with Hr-TB (odds ratio, 2.39; 95% confidence interval, 1.14, 4.70; P =.015). Thirteen (20%) isoniazid-resistant isolates were found in 5 putative transmission clusters based on a single nucleotide polymorphism distance of ≤ 5. No patients in these transmission clusters were members of the same household. Adolescents are at higher risk for Hr-TB. Strains of isoniazid-resistant M tuberculosis are actively circulating in Haiti and transmission is likely occurring in community settings. [ABSTRACT FROM AUTHOR]

Background Adequate control of the global tuberculosis (TB) burden is limited by a lack of accurate measures of treatment efficacy. Current gold standard relies on sputum cultures, which often lag weeks behind time of sample collection. Previous studies have identified urinary N 1 ,N 12 -diacetylspermine (DiAcSpm) as a potential biomarker of active pulmonary TB (ATB). We aimed to quantify urinary DiAcSpm in participants being treated for ATB and identify its relationship to treatment response. Methods Longitudinal urine samples were obtained from two separate cohorts of participants treated for ATB. Cohort one consisted of 34 successfully treated ATB cases with urine collected at weeks 0, 2, 4, 8, 17, 26, and 52. Cohort two consisted of 35 ATB cases under two treatment arms: one arm was successfully treated with the standard therapy of rifampin, isoniazid, pyrazinamide, and ethambutol (RIPE), and the other arm received an experimental drug, which was later found to be ineffective against ATB. Urine from cohort two was collected at days 0, 2, 4, and 14. All samples were blinded, randomized, normalized to osmolality and urinary creatinine, and analyzed using high-performance liquid chromatography-mass spectrometry. DiAcSpm concentrations were further tested using ELISA. Results Using linear-mixed modeling that adjusted for age, sex, and participant weight, we found that urinary DiAcSpm significantly decreased by week 2 of successful treatment in both cohorts (P < 0.0001). DiAcSpm levels remained unchanged in the ineffective experimental drug group (cohort two), significantly differentiating treatment success and failure by day 14 (P < 0.0001). Additionally, concentrations of urinary DiAcSpm positively correlate with sputum mycobacterial burden (P = 0.0002).These findings were consistent across both methods of detection. Conclusion Our results suggest that urinary concentrations of DiAcSpm correlate with TB treatment outcome and mycobacterial disease burden, and have the potential to serve as an early biomarker of TB treatment efficacy. Disclosures All Authors: No reported Disclosures. [ABSTRACT FROM AUTHOR]