BackgroundNontuberculous mycobacterial (NTM) infections cause morbidity worldwide. They are difficult to diagnose in resource-limited regions, and most patients receive empiric treatment for tuberculosis (TB). Our objective here is to evaluate the potential impact of NTM diseases among patients treated presumptively for tuberculosis in Mali.MethodsWe re-evaluated sputum specimens among patients newly diagnosed with TB (naïve) and those previously treated for TB disease (chronic cases). Sputum microscopy, culture and Mycobacterium tuberculosis drug susceptibility testing were performed. Identification of strains was performed using molecular probes or sequencing of secA1 and/or 16S rRNA genes.ResultsOf 142 patients enrolled, 61 (43%) were clinically classified as chronic cases and 17 (12%) were infected with NTM. Eleven of the 142 (8%) patients had NTM disease alone (8 M. avium, 2 M. simiae and 1 M. palustre). All these 11 were from the chronic TB group, comprising 11/61 (18%) of that group and all were identified as candidates for second line treatment. The remaining 6/17 (35.30%) NTM infected patients had coinfection with M. tuberculosis and all 6 were from the TB treatment naïve group. These 6 were candidates for the standard first line treatment regimen of TB. M. avium was identified in 11 of the 142 (8%) patients, only 3/11 (27.27%) of whom were HIV positive.ConclusionsNTM infections should be considered a cause of morbidity in TB endemic environments especially when managing chronic TB cases to limit morbidity and provide appropriate treatment.

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This study indicates a low level of primary drug resistance in Bamako, affirms the importance of using correct drug regimens, and suggests that the MTB T1 strain may be associated with the development of resistance.

Background MDR-TB is a major threat to global TB control. In 2015, 580,000 were treated for MDR-TB worldwide. The worldwide roll-out of GeneXpert MTB/RIF ® has improved diagnosis of MDR-TB; however, in many countries laboratories are unable to assess drug resistance and clinical predictors of MDR-TB could help target suspected patients. In this study, we aimed to determine the clinical factors associated with MDR-TB in Bamako, Mali. Methods We performed a cross-sectional study of 214 patients with presumed MDR-TB admitted to University of Bamako Teaching Hospital, Point-G between 2007 and 2016. We calculated crude and adjusted odds ratios for MDR-TB disease diagnosis using SPSS. Results We found that age ≤40years (OR = 2.56. 95% CI: 1.44–4.55), two courses of prior TB treatment (OR = 3.25,95% CI: 1.44–7.30), TB treatment failure (OR = 3.82,95% CI 1.82–7.79), sputum microscopy with 3+ bacilli load (OR = 1.98, 95% CI: 1.13–3.48) and a history of contact with a TB patient (OR = 2.48, 95% CI: 1.11–5.50) were significantly associated with confirmation of MDR-TB disease. HIV was not a risk factor for MDR-TB (aOR = 0.88, 95% CI: 0.34–1.94). Conclusion We identified several risk factors that could be used to identify MDR-TB suspects and prioritize them for laboratory confirmation. Prospective studies are needed to understand factors associated with TB incidence and clinical outcomes of TB treatment and disease.

Automated sequence analysis of a 410-bp region of the oxyR gene in 105 Mycobacterium tuberculosis complex isolates identified a polymorphic nucleotide that differentiated Mycobacterium bovis isolates from other complex members. All 29 M. bovis isolates sequenced had an adenine residue at nucleotide 285, whereas all 76 other complex isolates had a guanine residue. PCR-restriction fragment length polymorphism analysis of oxyR with restriction endonuclease AluI in an additional 255 complex isolates from widespread intercontinental sources confirmed and extended the unique association of adenine at position 285 with M. bovis isolates.