Factors Influencing Sputum Conversion among Smear-Positive Pulmonary Tuberculosis Patients in Morocco

Background: Sputum smear positive pulmonary tuberculosis patients expel infectious viable bacilli for a period following commencement of treatment. Objective: To determine the time to sputum smear conversion and study the factors influenceng it. Design: A prospective study was undertaken at our hospital in Rabat over a six months period on a cohort of 119 sputum smear positive patients. Patients were followed up fortnightly. At each follow up, specimens were collected and processed for microscopy using standard protocol. Results: 96.6% of our patients completed the study (4 deaths). Sputum conversion rate was 42% after two weeks, 73% after one month, and 95% after two months. Univariate and stepwise regression analysis showed that patients who had high smear grading, military, bilateral radiologic lesions were more likely to undergo delayed or non-conversion [P Conclusion: Since viable bacilli continue to be expelled for up to two months, infection control measures should be maintained for such time. Patients with high smear grading, miliary, bilateral radiologic lesions need to be monitored more closely.