Crude bacterial extracts of two new Streptomyces sp isolates as bio-colorants for textile dyeing

Renewed demand for incorporation of natural dyes (bio-colorants) in textile industry could be met through biotechnological production of bacterial pigments. Two new Streptomyces strains (NP2 and NP4) were isolated for the remarkable ability to produce diffusible deep blue and deep red pigment into fermentation medium. Crude mycelial extracts of both strains were used as bio-colorants in conventional textile dyeing procedures avoiding downstream purification procedures. The yields of bio-colorants obtained in this way were 62 and 84 mg per g of mycelia for Streptomyces sp. NP2 and Streptomyces sp. NP4, respectively. Through nuclear magnetic resonance analysis of crude extracts before and after dyeing procedures, it was shown that both extracts contained prodigiosin-like family of compounds that exhibited different dyeing capabilities towards different textile fibers. Polyamide and acrylic fibers were colored to the deepest shade, polyester and triacetate fibers to a noticeable, but much lower shade depth, while cotton and cellulosic fibers stained weakly. These results confirmed that crude bacterial extracts had the characteristics similar to those of ionic and disperse dyes, which was consistent with the identified polypyrrolic prodigiosin-like structures

Bacterial and host determinants of cough aerosol culture positivity in patients with drug-resistant versus drug-susceptible tuberculosis

A burgeoning epidemic of drug-resistant tuberculosis threatens to derail global control efforts. Although the mechanisms remain poorly clarified, drug-resistant strains are widely believed to be less infectious than drug-susceptible strains. Consequently, we hypothesised that lower proportions of drug-resistant TB patients would have culturable Mycobacterium tuberculosis from respirable cough-generated aerosols compared to drug-susceptible TB patients, and that multiple factors, including mycobacterial genomic variation, would predict culturable cough aerosol production. We enumerated colony forming units (CFU) in aerosols (≤10μm) from 500 tuberculosis patients (227 with drug-resistance), compared clinical characteristics, and performed mycobacterial whole genome sequencing, dormancy phenotyping, and drug susceptibility analyses on M. tuberculosis from sputum. After considering treatment duration, we found that almost half of drug-resistant tuberculosis patients were cough aerosol culture-positive. Surprisingly, neither mycobacterial genomic variants, lineage, nor dormancy status predicted cough aerosol culture-positivity. However, mycobacterial sputum bacillary load and clinical characteristics, including a lower symptom score and stronger cough, were strongly predictive; thereby supporting targeted transmission-limiting interventions. Effective treatment largely abrogated cough aerosol culture-positivity, however, this was not always rapid. These data question current paradigms, inform public health strategies, and suggest the need to redirect tuberculosis transmission-associated research efforts towards host-pathogen interactions