Factors Influencing Early Sputum Culture Conversion in Pulmonary Drug-resistant Tuberculosis

Introduction: India bears the highest global burden of tuberculosis (TB), with multidrug-resistant TB (MDR-TB) posing substantial treatment challenges. Sputum culture conversion is a vital indicator of treatment response and an early predictor of success in drug-resistant TB (DR-TB). This study aimed to evaluate the time to early sputum culture conversion (within 6 months) in DR-TB patients and identify factors influencing this outcome across different resistance patterns: MDR, MDR with fluoroquinolone resistance, MDR with second-line injectable resistance, and extensively DR-TB (XDR-TB). Methods: This prospective cross-sectional observational study was conducted in India. Seventy-four DR-TB patients enrolled between January and October 2019 were assessed. Demographic data, comorbidities, and culture conversion times were analyzed using Chi-square tests and univariate logistic regression. P <0.05 was considered statistically significant. Results: Among the 74 patients (62.2% male; mean age 30 years), most MDR-TB patients (52%) achieved culture conversion within 3 months, while pre-XDR and XDR cases mostly converted within 2 months. Smoking ( P = 0.03), low body mass index (BMI) ( P = 0.025), cavitary lesions on chest X-ray ( P = 0.01), and lower socioeconomic status ( P = 0.02) were significantly associated with delayed conversion. Conclusion: Early sputum culture conversion is a key milestone in DR-TB treatment. Addressing modifiable risk factors such as smoking, undernutrition, and cavitary disease may improve outcomes. Further studies are needed to identify interventions to accelerate culture conversion and enhance treatment success.