Conversion rate at two-month follow-up of smear-positive tuberculosis patients in Burkina Faso

SETTING: Burkina Faso, West Africa. OBJECTIVE: 1) To determine the trend of sputum smear conversion rates at the 2-month follow-up of new smear-positive tuberculosis (TB) patients; and 2) to compare conversion rates in cured TB patients and treatment failures. DESIGN: Retrospective cohort study based on TB registers from all 80 diagnostic and treatment centres from 1995 to 2003. The conversion rate was defined as the number of negative results divided by the number of smear-positive patients for whom the 2-month follow-up examination was completed. RESULTS: The 2-month follow-up completion rate was 92.1%; it increased from 86.3% in 1996 to 94.3% in 2003. The conversion rate was 82.9%, increasing from 76.3% in 1995 to 87.9% in 1997 and falling to 80.3% in 2003. The cure rate was higher among patients who were smear-negative at the 2-month follow-up (77.3%) CONCLUSION: The conversion rate was satisfying, but had declined since 1997, which may be a matter of concern. This could be due to patient characteristics such as associated conditions (human immunodeficiency virus, malnutrition) or to drug management (ineffective administration of drugs even under directly observed treatment, insufficient dosages, resistance). Thorough research is needed to elucidate this negative trend

Biotechnology approaches to overcome biotic and abiotic stress constraints in legumes

Biotic and abiotic stresses cause significant yield losses in legumes and can significantly affect their productivity. Biotechnology tools such as marker-assisted breeding, tissue culture, in vitro mutagenesis and genetic transformation can contribute to solve or reduce some of these constraints. However, only limited success has been achieved so far. The emergence of “omic” technologies and the establishment of model legume plants such as Medicago truncatula and Lotus japonicus are promising strategies for understanding the molecular genetic basis of stress resistance, which is an important bottleneck for molecular breeding. Understanding the mechanisms that regulate the expression of stress-related genes is a fundamental issue in plant biology and will be necessary for the genetic improvement of legumes. In this review, we describe the current status of biotechnology approaches in relation to biotic and abiotic stresses in legumes and how these useful tools could be used to improve resistance to important constraints affecting legume crops.E. Prats is funded by an European Marie Curie Reintegration Grant, N. Rispail by (FP5) Eufaba project. Our work in this area is supported by Spanish CICYT project AGL-2002-03248 and European Union project FP6-2002-FOOD-1-506223. K. Singh’s work in this area is supported in part by the Grains Research and Development Corporation (GRDC) and the Department of Education, Science and Training (DEST) in Australia.Peer reviewe