Evaluating the cost-effectiveness of TB diagnostic strategies in HIV-positive patients in Lusaka, Zambia

Abstract

Background: According toWHO, CDC, IDSA and ATS guidelines, atients with pulmonary tuberculosis (Tb) can be considered as on infectious when: 1) they are receiving multiple drugs for 2 to weeks; 2) there is an improvement in clinical condition; 3) the ikelihood of MDR-Tb is very small. Objective: To determine the ime for sputum reversion since the start of anti-Tb treatment in risoners from four jails in Medellin and Bucaramanga, Colombia etween May 2010 to April 2011. Methods: Prospective cohort study. All prisoners diagnosed ith Tb by sputum smear or culture were followed for two years: onthly for the first six months after the start of treatment, imonthly the next sixmonths, and quarterly the second year. Durng follow-up, we took two spontaneous and one induced sputum amples for auramine-rodhamine stain, and cultures in thin layer gar, Lowestein-Jensen andMGIT for the both first samples.We did ime to event analysis. Results: We could follow 45 of 47 positive patients (one was ransferred to another jail and one Tb-related death). The median or sputum smear reversion was 33 days (IQR: 31-60), and for culure was 55 days (IQR: 32-68). 90% of the patients had sputum mear and culture negative at 102 days. The time for sputum to ecome negative by culture had a positive correlation with the putum grade at the moment of diagnosis: negative smear with ositive culture= median 31.5 days, smear with 1+=58.5 days, mear 2+=62 days, and smear 3+=65 days (p value =0.007). Conclusion: After starting treatment the reversion of cultures ook twoormoremonths in≥50%cases. That is forcingus to rethink he recommendations about the isolation of patients with pulonary Tb in prisons, and suggests the need to use mycobacterial ultures on sputum to follow-up those patients.