Background: TB (Tuberculosis) is the second leading killer infectious disease after HIV (human immunodeficiency virus). Its incidence is worsened by development of multi-drug resistant and extensive drug resistant TB strains. Available treatment regimens are expensive, toxic and lengthy resulting to problems of non-adherence and inadequate response. Medicinal plants on the other hand may offer hope for developing alternative medicine for treatment of TB. This study evaluated the anti-tuberculosis activity of Echinops amplexicaulis. Materials and methods: Total crude extracts of E. amplexicaulis were tested for activity against a wild strain resistant to Rifampicin and Isoniazid (MDR), a fully susceptible laboratory strain (H37Rv) and Mycobacterium bovis (BCG strain) using disk diffusion method. MIC (minimum inhibitory concentration) was determined using Middlebrook 7H9 broth. The strains were sub-cultured on Middlebrook 7H10 medium and MBC (minimum bactericidal concentration) determined. Susceptibility was evaluated by measuring zones of inhibition; MIC was obtained as the lowest concentration with no significant growth as shown by clog formation of MTB (Mycobacteria tuberculosis) cells on the walls of the macro broth tube and MBC was obtained as the lowest concentration that inhibited growth of MTB colonies on Middlebrook 7H10 medium. Results: The extract showed a significant effect at a concentration of 50 mg/mL against all the three test strains F (2, 18) = 437.7, p = 0.00. It exhibited a MIC of 0.0488 mg/mL against MDR-TB and M. bovis. Its MBC was the same at 0.0977 mg/mL against both MDR TB and M. bovis. The MIC was much lower (0.0122 mg/mL) for the H37Rv strain. Terpenoids, alkaloids and tannins were present in large amount in the extract while saponins were present in small amounts. Flavonoids were not detected in the extract. Conclusion: E. amplexicaulis has the potential to be developed into new anti-TB drug and outcome of the study supports the folkloric claims of anti-tuberculosis activity of the plant.

There is a high prevalence of phenotypic PZA resistance among TB patients in Uganda. The low sensitivity of pncA gene sequencing confirms the already documented discordances suggesting other mechanisms of PZA resistance in Mycobacterium tuberculosis.data collection and analysis, decision to publish, or preparation of the manuscript.

Background The Global Laboratory Initiative (GLI) guidelines recommend to repeat GeneXpertMTB/RIF (XpertMTB/RIF) in patients with a low-pretest probability of rifampicin-resistance (RR). Design/Methods In a cross-sectional study using results of sputum specimens collected from participants screened for the STREAM 2 trial. We recruited all patients with XpertMTB/RIF RR-TB detected who were referred for RR/MDR-TB treatment initiation at Mulago National Referral Hospital, Kampala, between September 2017 and October 2019. At baseline, smear microscopy, repeat XpertMTB/RIF, Xpert Ultra and MTBDRplus assays were done on sputum specimens. Culture-based drug-susceptibility testing (DST) were done on discordant specimens. We analysed the prevalence and factors associated with discordance between initial and repeat XpertMTB/RIF RR and false XpertMTB/RIF RR. False XpertMTB/RIF RR was defined as no RR detected by any of Xpert Ultra, LPA or culture DST (reference comparator). Results A total of 126/130 patients had repeat XpertMTB/RIF results of which, 97 (77.0%) had M. tuberculosis detected of whom, 81 (83.5%) had RR detected, and 1 (1.0%) had RR indeterminate. The prevalence of discordant XpertMTB/RIF RR was 15/96 (15.6%) whereas false XpertMTB/RIF RR prevalence was 10/96 (10.4%). Low bacillary load sputum specimens were more likely to have discordant XpertMTB/RIF RR and false XpertMTB/RIF RR results, aOR (p-value: 95%CI), 0.04 (0.01; 0.00-0.37) and 0.02 (0.01; 0.01-0.35) respectively. Conclusion Our findings show a high false-positive rifampicin resistance rate in low TB burden patients, which calls for repeat testing in order to prevent unnecessary prescription of anti MDR-TB therapy.

We recruited all patients with Xpert Rifampicin-Resistant (RR)-TB detected, referred to the MDR-TB ward at Mulago National Referral Hospital, Kampala, Uganda for MDR-TB treatment initiation between September 2017 and October 2019. Using baseline samples collected for patients screened for STREAM 2 trial, smear microscopy, repeat Xpert test and first-line MTBDRplus assay were done. Culture-based drug-susceptibility testing was done on discordant samples. We analysed for factors associated with discordant results and false RR as determined as no RR detected by at least two of the methods used (reference standard). Of 126/130 patients who had results of repeat Xpert, 97 (77.0%) had M. tuberculosis detected of which 81 (83.5%) had RR-detected, 1 (1.0%) indeterminate. A total of 10/96 (10.4%) patients were rifampicin susceptible by at least two of the methods. Having false Xpert RR was associated with low bacillary load measured by high cycle threshold (Ct) value i.e. low (Ct 22–28) and very low (Ct > 28) of the initial Xpert test 0.09 (0.05; 0.01–1.08) and 0.02 (0.01; 0.01–0.35) respectively. Our results show that a repeat Xpert test on another sputum sample for patients with initial low M. tuberculosis detected RR-detected, would exclude 10% of the TB patients from unnecessary MDR-TB treatment initiation.

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