BioProject

Mycobacterium tuberculosis Beijing family is an emergent pathogen widely dispersed across the world. More...

Mycobacterium tuberculosis Beijing family is an emergent pathogen widely dispersed across the world. In Colombia a variant of this genotype, the Beijing Like SIT 190 strains are the third most frequently isolated genotype after LAM and Harlem, becoming an important public health concern due to the high virulence and drug resistance characteristics of this aggressive bacteria.

Beijing genotype was originally described in 1995 by Van Soolingen et al., however this genotype has evolutionated since 6000 years ago and with the availability of genomic typing methods and DNA sequencing this genotype is classified in six ancestral clonal complexes and one sublineage of recent evolution. In Colombia the circulation of Beijing genotype has been reported since 1997 and are characterized by the absence of the 1 to 34 and 40 spacers using spoligotyping as typing method and are identified as Beijing Like strains. In this study, the progressive pulmonary TB model in BALB/c mice was used; groups of 50 male animals per group were anaesthetized with sevoflurane (100 uL per mice) and infected by intratracheal inoculation with 250.000 bacteria/100uL of each strain. At day 1, 3, 7, 14, 21, 28 and 60 (with surviving mice) after infection groups of six mice were euthanized by exanguination under anesthesia with pentobarbital. Left lungs lobes and spleens were removed for CFU processing and histopathology. Here, higher virulence of Beijing like strain was characterized by earlier and higher mortality, higher pulmonary bacillary loads with extensive tissue damage (pneumonia). In contrast, classical Beijing 391 strain induced slower disease progression, allowing animals live up to day 60, however at this day the pulmonary histology showed necrotic areas, but with lower bacillary burdens than the animals infected with Beijing Like Less...