Background: Production of antibiotics to inhibit competitors affects soil microbial community composition and contributes to disease suppression. In this work, we characterized whether Streptomyces bacteria, prolific antibiotics producers, inhibit a soil borne human pathogenic microorganism, Streptomyces sudanensis. S. sudanensis represents the major causal agent of actinomycetomaa largely under-studied and dreadful subcutaneous disease of humans in the tropics and subtropics. The objective of this study was to evaluate the in vitro S. sudanensis inhibitory potential of soil streptomycetes isolated from different sites in Sudan, including areas with frequent (mycetoma belt) and rare actinomycetoma cases of illness.Results: Using selective media, 173 Streptomyces isolates were recovered from 17 sites representing three ecoregions and different vegetation and ecological subdivisions in Sudan. In total, 115 strains of the 173 (66.5%) displayed antagonism against S. sudanensis with different levels of inhibition. Strains isolated from the South Saharan steppe and woodlands ecoregion (Northern Sudan) exhibited higher inhibitory potential than those strains isolated from the East Sudanian savanna ecoregion located in the south and southeastern Sudan, or the strains isolated from the Sahelian Acacia savanna ecoregion located in central and western Sudan. According to 16S rRNA gene sequence analysis, isolates were predominantly related to Streptomyces werraensis, S. enissocaesilis, S. griseostramineus and S. prasinosporus. Three clusters of isolates were related to strains that have previously been isolated from human and animal actinomycetoma cases: SD524 (Streptomyces sp. subclade 6), SD528 (Streptomyces griseostramineus) and SD552 (Streptomyces werraensis). Conclusion:The in vitro inhibitory potential against S. sudanensis was proven for more than half of the soil streptomycetes isolates in this study and this potential may contribute to suppressing the abundance and virulence of S. sudanensis. The streptomycetes isolated from the mycetoma free South Saharan steppe ecoregion show the highest average inhibitory potential. Further analyses suggest that mainly soil properties and rainfall modulate the structure and function of Streptomyces species, including their antagonistic activity against S. sudanensis.

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We report a case of pulmonary nocardiosis in a 41-year-old asthma patient. Chest radiographs showed bilateral air space and consolidations. Acid-fast branching filaments were demonstrated in sputum, and the grown organism was identified phenotypically and confirmed using 16S rDNA sequencing (accession no. KX500116). The patient received a combination of medical treatments, but developed complications, which were managed over the next 3 months, after which she was discharged. Pulmonary nocardiosis should be considered in patients undergoing steroid therapy or when a chronic infection does not respond to first-line treatment.

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The purpose of this study was to investigate streptomycete populations in desert and savanna ecozones in Sudan and to identify species based on 16S rRNA gene sequences. A total of 49 different Streptomyces phenotypes (22 from sites representing the desert and semi-desert ecozone; 27 representing the savanna ecozone) have been included in the study. The isolates were characterized phenotypically and confirmed using 16S rRNA gene sequence analysis. The two ecozones showed both similarities and uniqueness in the types of isolates. The shared species were in cluster 1 (Streptomyces (S.) werraensis), cluster 2 (Streptomyces sp.), cluster 3 (S. griseomycini-like), and cluster 7 (S. rochei). The desert ecozone revealed unique species in cluster 9 (Streptomyces sp.) and cluster 10 (S. griseomycini). Whereas, the savanna ecozone revealed unique species in cluster 4 (Streptomyces sp.), cluster 5 (S. albogriseolus/ S. griseoincarnatus), cluster 6 (S. djakartensis), and cluster 8 (Streptomyces sp.). Streptomycetes are widely distributed in both desert and the savanna ecozones and many of these require full descriptions. Extending knowledge on Streptomyces communities and their dynamics in different ecological zones and their potential antibiotic production is needed.

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This study was conducted to investigate the effect of inclusion dried taro waste (DTW) without or with dried yeast (DY) in sheep rations on digestibility, rumen fermentation activity, blood parameters and growth performance of Ossimi lambs. Comparative feeding trial was applied with twenty four growing male lambs, averaging 21.5±2 kg of body weight where they were randomly divided into four similar groups (6 each) for feeding period of 150 days. The experimental rations were formulated as followed: 65% CFM+17.5% rice straw (RS) +17.5% DTW (R1); 65% CFM+17.5% RS+17.5% DTW with dried yeast (R2); 65% CFM+35% DTW (R3) and 65% CFM+35% DTW with dried yeast (R4). Dried yeast (Saccharomyces cerevisiae) was added at the rate of 5g/h/d. Digestibility trials were conducted with Ossimi rams to evaluate the digestibility and feeding values of the experimental rations. Results indicated that most nutrient digestibilities were markedly improved with the higher level of DTW in rations, where R3 and R4 had the highest (P<0.05) digestibility values for most nutrients versus those of the lower DTW ration, without or with DY (R1& R1). Feeding values expressed as TDN did not significantly differ among the experimental rations, while DCP values were significantly improved with increasing the level of DTW, without or with DY. Addition of DY to R2 and R4 rations had no significant effect on feeding values expressed as TDN and DCP. Results of rumen liquor pH values were almost insignificant increased with increasing the proportion of DTW in rations without or with DY. Also, there were no significant differences in NH 3-N and TVFA´s concentrations among the experimental groups, with the best values being occurred with the low level of DTW-ration with DY additive (R2). No significant differences were observed among experimental groups concerning the all blood parameters except for albumin that was significant higher for animals fed ration contained only DTW with yeast (R4), while the differences respecting this item did not significant among the other treatments. Average daily gain was significantly higher with tested ration R2 than that of R3 or R4, but insignificant higher than that of R1ration. Daily DM intake was nearly comparable among groups. The best values of feed conversion and economic efficiency were observed with lambs fed ration that contained DTW + RS + DY (R2) while; these items did not improve with increasing DTW level. It could be concluded that DTW is a nutritious fodder ingredient for ration formulation for small ruminant. Therefore the low level of DTW (17.5%) especially with yeast is highly recommended in practical feeding of growing lambs.