Phylogenomic and genomic analysis reveals unique and shared genetic signatures of Mycobacterium kansasii complex species.

Species belonging to the Mycobacterium kansasii complex (MKC) are frequently isolated from humans and the environment and can cause serious diseases. The most common MKC infections are caused by the species M. kansasii (sensu stricto), leading to tuberculosis-like disease. However, a broad spectrum of virulence, antimicrobial resistance and pathogenicity of these non-tuberculous mycobacteria (NTM) are observed across the MKC. Many genomic aspects of the MKC that relate to these broad phenotypes are not well elucidated. Here, we performed genomic analyses from a collection of 665 MKC strains, isolated from environmental, animal and human sources. We inferred the MKC pangenome, mobilome, resistome, virulome and defence systems and show that the MKC species harbours unique and shared genomic signatures. High frequency of presence of prophages and different types of defence systems were observed. We found that the M. kansasii species splits into four lineages, of which three are lowly represented and mainly in Brazil, while one lineage is dominant and globally spread. Moreover, we show that four sub-lineages of this most distributed M. kansasii lineage emerged during the twentieth century. Further analysis of the M. kansasii genomes revealed almost 300 regions of difference contributing to genomic diversity, as well as fixed mutations that may explain the M. kansasii's increased virulence and drug resistance.

Experiencia en el uso del tratamiento del ultrasonido endoscópico en la unidad de exploraciones digestivas del Hospital de Clínicas Caracas / Experience in the use the treatment ultrasonics endoscopy of the unity of explorations digestives of Hospital of Clinics Caracas

Desde su introducción en 1975, el ultrasonido endoscópico (USE) se ha convertido en un método útil para estudiar lesiones del tracto digestivo desde tumores submucosos hasta estadios de cánceres avanzados. En este trabajo se evaluaron los primeros 100 casos de USE realizados desde marzo de 1998 hasta mayo de 1999 en la unidad de exploraciones digestivas del Hospital de Clínicas Caracas. La indicación más frecuente fue para estadio de carcinoma (50 por ciento) seguida de evaluación de tumores submucosos (21 por ciento). Las lesiones se localizaron más frecuentemente a nivel mural en 82 pacientes; 60 pacientes presentaron patología maligna, de estos, el 41 por ciento se ubicaba en estómago. Se concluyó que el USE es un método útil, con bajo porcentaje de complicaciones, que permite el estadio más preciso de las lesiones del tracto digestivo y órganos adyacentes (hígado, páncreas, mediastino), proporcionando una validación adecuada del pronóstico de los pacientes e influenciado las decisiones terapéuticas