The impact of changing the diagnostic algorithm for TB in Manicaland, Zimbabwe.

SETTING: Governmental health facilities performing TB diagnostics in Manicaland, Zimbabwe. OBJECTIVE: To investigate the effect of making Xpert® MTB/RIF the primary TB diagnostic for all patients presenting with presumptive TB on 1) the number of samples investigated for TB, 2) the proportion testing TB-positive, and 3) the proportion of unsuccessful results over time. DESIGN: This retrospective study used data from GeneX-pert downloads, laboratory registers and quality assurance reports between 1 January 2017 and 31 December 2018. RESULTS: The total number of Xpert tests performed in Manicaland increased from 3,967 in the first quarter of 2017 to 7,011 in the last quarter of 2018. Mycobacterium tuberculosis DNA was detected in 4.9-8.6% of the samples investigated using Xpert, with a higher yield in 2017 than in 2018. The overall proportion of unsuccessful Xpert assays due to "no results", errors and invalid results was 6.3%, and highly variable across sites. CONCLUSION: Roll out of more sensitive TB diagnostics does not necessarily result in an increase of microbiologically confirmed TB diagnosis. While the number of samples tested using Xpert increased, the proportion of TB-positive tests decreased. GeneXpert soft- and hardware infrastructure needs to be strengthened to reduce the rate of unsuccessful assays and therefore, costs and staff time

Effects of water stress at different growth stages on yield and yield components of common bean (Phaseolus vulgaris)

Common bean (Phaseolus vulgaris L.) has great potential for improving human nutrition due to its high protein content. However, water stress was found to be one of the major constraints to common bean production in Zimbabwe. A field experiment was therefore carried out at Agricultural Research Trust farm in early summer of 2004, and repeated at the same time in 2005, to determine the effect of water stress at different growth stages on grain yield and yield components of three common bean varieties. The experimental design was a 3×5 split-plot in a Randomised Complete Block Design; with water stresses as the main plot factor (withholding irrigation for a period of twenty-one days at; two weeks after emergence (WAE), four WAE, at flowering and two weeks after flowering (WAF) as well as non-stressed control) and the varieties in the subplot factor (Onyx, Pan 329 and Dark Red Kidney). Water stress significantly reduced grain yield (p<0.05) with flowering and two WAF stages being the most sensitive, and vegetative stage being the least sensitive. Water stress also produced significant effects (p<0.05) on yield components. Water stress during flowering and after flowering significantly reduced number of seed per pod and seed weight. For maximum yield, water stress must be avoided during flowering and pod-filling stages, so early planting is important under dry land planting

Comparative Analysis of Genexpert MTB/Rif version 4 and Genexpert MTB/Rif Ultra on Frozen Sputum

Objectives: The aim of this study was to carry out a comparative analysis using Genexpert MTB/Rif Ultra (Ultra) on clinical samples of frozen sputum previously analyzed on Genexpert MTB/Rif version 4 (Xpert)and Mycobacterium Growth Indicator Tube (MGIT) culture.Design: The study employed both retrospective and prospective cross sectional design.Setting: Mutare Provincial Hospital Manicaland, Zimbabwe.Subjects: One hundred and nine de-identified frozen sputum.Interventions: Ultra test.Main Outcome Measures: Ultra results.Results: There was 96/109 (88%) concordance and 10/109 (9.2%) discordance between Xpert and Ultra. Sputum frozen for 7 years then analyzed on Ultra performed better than 7 years previously when it was analyzed as raw sputum on Xpert using MGIT as gold standard (95.6% and 93.2% respectively).The results were comparable and statistically significant, kappa analysis between Xpert and frozen sputum Ultra was not statistically significant showing a slight level of agreement of 0.147 (p value =0.079), 95% CI (-0.1078, 0.4018).Conclusion: Results of Ultra on frozen sputum correlate reasonably well. The study findings show that TB positive frozen sputum from presumptive DRTB, run on Ultra after 7 years freezing can perform better than previously run Xpert results compared to MGIT as gold standard. In light of the research findings, potential implication are that to save on cost, comparison of performance of newly diagnosed tests can be done using frozen sputum, pre run on panel of TB tests