RESUMO
Mycobacterium tuberculosis infection and nontuberculous mycobacteria (NTM) infections exhibit similar clinical symptoms; however, the therapies for these two types of infections are different. Therefore, the rapid and accurate identification of M. tuberculosis and NTM species is very important for the control of tuberculosis and NTM infections. In the present study, a Cas12a/guide RNA (gRNA)-based platform was developed to identify M. tuberculosis and most NTM species. By designing species-specific gRNA probes targeting the rpoB sequence, a Cas12a/gRNA-based platform successfully identified M. tuberculosis and six major NTM species (Mycobacterium abscessus, Mycobacterium intracellulare, Mycobacterium avium, Mycobacterium kansasii, Mycobacterium gordonae, and Mycobacterium fortuitum) without cross-reactivity. In a blind assessment, a total of 72 out of 73 clinical Mycobacterium isolates were correctly identified, which is consistent with previous rpoB sequencing results. These results suggest that the Cas12a/gRNA-based platform is a promising tool for the rapid, accurate, and cost-effective identification of both M. tuberculosis and NTM species.
Assuntos
Proteínas de Bactérias/genética , Proteínas Associadas a CRISPR/genética , Endodesoxirribonucleases/genética , Mycobacterium/classificação , Sondas RNA , RNA Guia de Cinetoplastídeos/genética , Tuberculose/diagnóstico , Sistemas CRISPR-Cas , Humanos , Mycobacterium/isolamento & purificação , Infecções por Mycobacterium não Tuberculosas/microbiologia , Complexo Mycobacterium avium/genética , Complexo Mycobacterium avium/isolamento & purificação , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/isolamento & purificação , Micobactérias não Tuberculosas/genética , Micobactérias não Tuberculosas/isolamento & purificação , RNA Ribossômico 16S/genética , Sensibilidade e Especificidade , Tuberculose/microbiologiaRESUMO
Mode coupling characteristics in metal-coated microsphere are comprehensively studied by analytical method with Mie theory. The dispersion relation, field distribution and Q factor of the eigenmodes are calculated according to the modal eigenequation. In metal-coated microcavity, symmetric SPP mode can couple with asymmetric SPP mode and TM eigenmodes strongly at the different characteristic radius of microsphere. In the coupling range, the generated supermode possesses both high Q factor and high surface enhancement factor, which is expected to have many interesting potential applications. Furthermore, the sensitivity and figure of merit of supermode in biochemical sensing applications has been studied. The results show that both high sensitivity and large figure of merit can be achieved simultaneously.