RESUMEN
The present study aimed to determine the genetic diversity of isolates of Mycobacterium tuberculosis (Mtb) from presumed drug-resistant tuberculosis patients from several states of Brazil. The isolates had been submitted to conventional drug susceptibility testing for first- and second-line drugs. Multidrug-resistant (MDR-TB) (54.8%) was the most frequent phenotypic resistance profile, in addition to an important high frequency of pre-extensive resistance (p-XDR-TB) (9.2%). Using whole-genome sequencing (WGS), we characterized 298 Mtb isolates from Brazil. Besides the analysis of genotype distribution and possible correlations between molecular and clinical data, we determined the performance of an in-house WGS pipeline with other online pipelines for Mtb lineages and drug resistance profile definitions. Sub-lineage 4.3 (52%) was the most frequent genotype, and the genomic approach revealed a p-XDR-TB level of 22.5%. We detected twenty novel mutations in three resistance genes, and six of these were observed in eight phenotypically resistant isolates. A cluster analysis of 170 isolates showed that 43.5% of the TB patients belonged to 24 genomic clusters, suggesting considerable ongoing transmission of DR-TB, including two interstate transmissions. The in-house WGS pipeline showed the best overall performance in drug resistance prediction, presenting the best accuracy values for five of the nine drugs tested. Significant associations were observed between suffering from fatal disease and genotypic p-XDR-TB (p = 0.03) and either phenotypic (p = 0.006) or genotypic (p = 0.0007) ethambutol resistance. The use of WGS analysis improved our understanding of the population structure of MTBC in Brazil and the genetic and clinical data correlations and demonstrated its utility for surveillance efforts regarding the spread of DR-TB, hopefully helping to avoid the emergence of even more resistant strains and to reduce TB incidence and mortality rates.
RESUMEN
Foram utilizados dois métodos para detectar micobacteriemia em 50 pacientes com AIDS. 1.inoculaçäo direta em meio bifásico; 2.um sistema näo comercial de lise-centrifugaçäo. Os métodos demonstraram uma positividade de 50 por cento e 56 por cento, respectivamente. Os resultados demonstram que a cultura de sangue pode ser executada utilizando-se método näo comercial de lise-centrifugaçäo o qual é sensível, barato e pode ser um método alternativo confiável para o diagnóstico de micobacteriemia em países em desenvolvimento.
Asunto(s)
Humanos , Mycobacterium tuberculosis , Síndrome de Inmunodeficiencia Adquirida/complicaciones , Técnicas Bacteriológicas , Recolección de Muestras de Sangre , Medios de Cultivo , Mycobacterium tuberculosis/aislamiento & purificación , Síndrome de Inmunodeficiencia Adquirida/microbiología , Organización Mundial de la SaludRESUMEN
O efeito esporocida de preparaçöes contendo formaldeído nas concentraçöes de 4, 5, 6 e 8%, juntamente com álcool e quaternários de amônio, foi avaliado pela técnica da AOAC (The Association of Official Analytical Chemists). O tempo necessário para a destruiçäo dos esporos de Bacillus subtilis e Clostridium sporogenes foi, respectivamente, de 8 e 18 horas. É importante assinalar que as soluçöes contendo 4 e 5% de formaldeído näo apresentam os vapores irritantes täo característicos deste desinfetante quando utilizado em concentraçöes mais altas