Factors Influencing Sputum Smear and Culture Conversion Time among Patients with Pulmonary Tuberculosis

Introduction: Pulmonary tuberculosis is a contagious bacterial infection that involves the lungs and it may spread to other organs. Sputum smear and culture conversion are important indicators for the effectiveness of treatment and the infectivity of the patient. The present study aims to find sputum smear and culture conversion time and the factors that influence the conversion time among tuberculosis patients at National Tuberculosis Centre in Nepal. Methods: A total of 54 patients, who were diagnosed with laboratory confirmed pulmonary tuberculosis and under antitubercular therapy were monitored for sputum smear and culture conversion time. The blood specimens from each patient were processed for hemoglobin, platelets, erythrocyte sedimentation rate and blood glucose levels. Patient’s clinical history, risk factors that prolong conversion time and sociodemographic information were also collected by direct interview. Results: The mean sputum smear and culture conversion were found to be 54.4 days and 45.5 days respectively. Old age, smoking habit, low body mass index value, Treatment category II, initial bacillary load and abnormal erythrocyte sedimentation rate values were found to be associated with long sputum conversion time. Radiographic involvement of only left lungs, presence of fewer symptoms, aged between 15-45 years, having normal weight, without smoking habit and being married, were found to be associated with short sputum conversion time. Conclusions: The sputum microscopy, old age, smoking habit, low body mass index value, treatment category II, initial bacillary load and abnormal erythrocyte sedimentation rate value had been found to be significantly associated with long sputum conversion time.