The Neglected Contribution of Streptomycin to the Tuberculosis Drug Resistance Problem.

The airborne pathogen is responsible for a present major public health problem worsened by the emergence of drug resistance. has acquired and developed streptomycin (STR) resistance mechanisms that have been maintained and transmitted in the population over the last decades. Indeed, STR resistant mutations are frequently identified across the main lineages that cause tuberculosis outbreaks worldwide.

Heterogeneous Streptomycin Resistance Level Among Strains From the Same Transmission Cluster.

Widespread and frequent resistance to the second-line tuberculosis (TB) medicine streptomycin, suggests ongoing transmission of low fitness cost streptomycin resistance mutations. To investigate this hypothesis, we studied a cohort of 681 individuals from a TB epidemic in Portugal. Whole-genome sequencing (WGS) analyses were combined with phenotypic growth studies in culture media and in mouse bone marrow derived macrophages.

Photodynamic inactivation of Escherichia coli with cationic ammonium Zn(II) phthalocyanines.

The aim of this work was the development of a family of novel water soluble Zinc(II) phthalocyanines (Pc) for the photodynamic inactivation of Gram-negative bacteria. Pc derivatives 1a, 2a and 3a containing trimethylammonium groups with varied number and nature of the groups at peripheral positions were synthesized by cyclotetramerization of dimethyl amino substituted phthalonitriles in the presence of zinc powder, using 1-chloronaphthalene as a solvent, followed by cationization using dimethyl sulfate. The solubility, singlet oxygen generation ((1)O2) and stability/photostability of each Pc were evaluated as well as the affinity to bacterial cells and their photosensitizing potential against a recombinant bioluminescent Escherichia coli strain, used as a biological model for Gram negative bacteria.