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Viveiros M

Rapid determination of anti-tuberculosis drug resistance from whole-genome sequences

Mycobacterium tuberculosis drug resistance (DR) challenges effective tuberculosis disease control. Current molecular tests examine limited numbers of mutations, and although whole genome sequencing approaches could fully characterise DR, data complexity has restricted their clinical application.
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Enhancement of antibiotic activity by efflux inhibitors against multidrug resistant Mycobacterium tuberculosis clinical isolates from Brazil

Drug resistant tuberculosis continues to increase and new approaches for its treatment are necessary. The identification of M. tuberculosis clinical isolates presenting efflux as part of their resistant phenotype has a major impact in tuberculosis treatment. In this work, we used a checkerboard procedure combined with the tetrazolium microplate-based assay (TEMA) to study single combinations between antituberculosis drugs and efflux inhibitors (EIs) against multidrug resistant M. tuberculosis clinical isolates using the fully susceptible strain H37Rv as reference.
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Enhancing activity of antibiotics against Staphylococcus aureus: Zanthoxylum capense constituents and derivatives

Six compounds (1-6), isolated from the methanol extract of the roots of the African medicinal plant Zanthoxylum capense Thunb. (Rutaceae), and seven ester derivatives (7-13) were evaluated for their antibacterial activities and modulatory effects on the MIC of antibiotics (erythromycin, oxacillin, and tetracycline) and ethidium bromide (EtBr) against a Staphylococcus aureus reference strain (ATCC 6538). Using the same model, compounds 1-13 were also assessed for their potential as efflux pump inhibitors by a fluorometric assay that measures the accumulation of the broad range efflux pump substrate EtBr. Compounds 8 and 11 were further evaluated for their antibacterial, modulatory and EtBr accumulation effects against four additional S. aureus strains, which included two clinical methicillin-resistant S. aureus (MRSA) strains.
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Spectinamides: a challenge, a proof, and a suggestion

New drugs and shorter regimens are needed to fight resistant forms of tuberculosis. Screening of chemical libraries for mining hit compounds is the common approach to find new antituberculars. A new medicinal chemistry and biology directed research rational has recently been successfully described by Lee and coworkers in Nature Medicine.
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Unraveling Mycobacterium tuberculosis genomic diversity and evolution in Lisbon, Portugal, a highly drug resistant setting

Multidrug- (MDR) and extensively drug resistant (XDR) tuberculosis (TB) presents a challenge to disease control and elimination goals. In Lisbon, Portugal, specific and successful XDR-TB strains have been found in circulation for almost two decades.
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Gold nanoprobes for multi loci assessment of multi-drug resistant tuberculosis

Here we extend the Au-nanoprobe approach towards discriminating specific mutations within inhA and rpoB genes in PCR amplified DNA from isolates. Using a multiplex PCR reaction for these two genes, it is possible to assess both loci in parallel, and extend the potential of the Au-nanoprobe method to MDRTB molecular characterization with special application in the most frequent Portuguese genotypes.
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Design, synthesis and biological evaluation of novel isoniazid derivatives with potent antitubercular activity

The disturbing emergence of multidrug-resistant strains of Mycobacterium tuberculosis(Mtb) has been driving the scientific community to urgently search for new and efficient antitubercular drugs. Despite the various drugs currently under evaluation, isoniazid is still the key and most effective component in all multi-therapeutic regimens recommended by the WHO. This paper describes the QSAR-oriented design, synthesis and in vitro antitubercular activity of several potent isoniazid derivatives (isonicotinoyl hydrazones and isonicotinoyl hydrazides) against H37Rv and two resistant Mtb strains.
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Relatedness of Mycobacterium avium subspecies hominissuis clinical isolates of human and porcine origins assessed by MLVA

In this study, the analysis of Mycobacterium avium tandem repeats (MATRs) loci was adapted to evaluate the genetic diversity of epidemiological unrelated MAH clinical strains of human (n=28) and porcine (n=69) origins, collected from diverse geographical regions across mainland Portugal. These MAH isolates were found to be genetically diverse and genotypes are randomly distributed across the country.
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Rapid identification of veterinary-relevant Mycobacterium tuberculosis complex species using 16S rDNA, IS6110 and Regions of Difference-targeted dual-labelled hydrolysis probes

In this work we describe a rapid and robust two-step five-target probe-based real-time PCR identification algorithm, based on genomic deletion analysis, to identify the MTC species most commonly associated with TB in livestock and other animals.
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