RESUMO
Antimicrobial air filtration techniques have recently been widely studied to enhance indoor air quality and mitigate hazardous airborne microorganisms. Here, CuNPs were incorporated into a commercial polyester fiber surface and Scanning Mobility Particle Sizer was used to measure the adherence between fibers and nanoparticles. An acid pretreatment previous CuNP incorporation was effective against the particle release and enhanced the adhesion between particle and fiber. CuNP was a mixture of Cu0 and Cu2O with a diameter size of 90 nm (SEM micrographs). The permeability of the filter was low, in order of 10-9 m2. The activity against pathogens was tested in loco in a real environment using a filtration prototype apparatus. It was observed that the presence of CuNP mitigated the fungi and bacteria growth not only on the surface but also reduced microbe concentrations after passing through the filter. These results show that CuNP can be used as an inhibitor of various microorganisms, making them a good alternative for indoor environments to control indoor air quality.
RESUMO
Mycolic acids analysis by thin-layer chromatography (TLC) has been employed by several laboratories worldwide as a method for fast identification of mycobacteria. This method was introduced in Brazil by our laboratory in 1992 as a routine identification technique. Up to the present, 861 strains isolated were identified by mycolic acids TLC and by standard biochemical tests; 61% out of these strains came as clinical samples, 4% isolated from frogs and 35% as environmental samples. Mycobacterium tuberculosis strains identified by classical methods were confirmed by their mycolic acids contents (I, III and IV). The method allowed earlier differentiation of M. avium complex-MAC (mycolic acids I, IV and VI) from M. simiae (acids I, II and IV), both with similar biochemical properties. The method also permitted to distinguish M. fortuitum (acids I and V) from M. chelonae (acids I and II), and to detect mixed mycobacterial infections cases as M. tuberculosis with MAC and M. fortuitum with MAC. Concluding, four years experience shows that mycolic acids TLC is an easy, reliable, fast and inexpensive method, an important tool to put together conventional mycobacteria identification methods.