Medicinal plants from open-air markets in the State of Rio de Janeiro, Brazil as a potential source of new antimycobacterial agents.

Ethnopharmacological Relevance: Several medicinal plants are traditionally traded in open-air markets in Rio de Janeiro State (Brazil) to treat tuberculosis (TB) and related symptoms.

Aims Of The Study: Conduct a survey in the open-air markets of 20 cities of Rio de Janeiro State to find medicinal plants that are popularly used to treat tuberculosis and other related diseases and assess their in vitro antimycobacterial activity.

Materials And Methods: We used direct observation and semi-structured interviews and asked herbalists to list species (free listing) in order to gather data about the plant species most commonly used for lung problems.

Biological cost in Mycobacterium tuberculosis with mutations in the rpsL, rrs, rpoB, and katG genes.

When bacteria develop drug-resistant mutations, there is often an associated biological cost; however, some strains can exhibit low- or no-cost mutations. In the present study, a quantitative resazurin reduction assay was used to measure the biological cost of Mycobacterium tuberculosis isolates that contained different mutations in the rpsL, rrs, rpoB, and katG genes, and showed different resistance profiles. Biological costs were determined by comparing the growth curves of drug-resistant isolates with drug-susceptible strains.

Streptomycin resistance and lineage-specific polymorphisms in Mycobacterium tuberculosis gidB gene.

Mutations related to streptomycin resistance in the rpsL and rrs genes are well known and can explain about 70% of this phenotypic resistance. Recently, the gidB gene was found to be associated with low-level streptomycin resistance in Mycobacterium tuberculosis. Mutations in gidB have been reported with high frequency, and this gene appears to be very polymorphic, with frameshift and point mutations occurring in streptomycin-susceptible and streptomycin-resistant strains.