Discovery of Novel Chemical Series of OXA-48 β-Lactamase Inhibitors by High-Throughput Screening.

The major cause of bacterial resistance to β-lactams is the production of hydrolytic β-lactamase enzymes. Nowadays, the combination of β-lactam antibiotics with β-lactamase inhibitors (BLIs) is the main strategy for overcoming such issues. Nevertheless, particularly challenging β-lactamases, such as OXA-48, pose the need for novel and effective treatments.

Antibacterial activity of novel dual bacterial DNA type II topoisomerase inhibitors.

In this study, a drug discovery programme that sought to identify novel dual bacterial topoisomerase II inhibitors (NBTIs) led to the selection of six optimized compounds. In enzymatic assays, the molecules showed equivalent dual-targeting activity against the DNA gyrase and topoisomerase IV enzymes of Staphylococcus aureus and Escherichia coli. Consistently, the compounds demonstrated potent activity in susceptibility tests against various Gram-positive and Gram-negative reference species, including ciprofloxacin-resistant strains.

In vitro time-kill kinetics of dalbavancin against Staphylococcus spp. biofilms over prolonged exposure times.

Staphylococcus aureus and Staphylococcus epidermidis are leading pathogens of biofilm-related infections and represent the most common cause of osteomyelitis and biomedical implants infections. Biofilm-related infections usually require long-term antibiotic treatment, often associated to surgical interventions. Dalbavancin is a newer lipoglycopeptide approved for the treatment of acute skin and skin-structure infections caused by Gram-positive pathogens.

Virtual Screening Approach and Investigation of Structure-Activity Relationships To Discover Novel Bacterial Topoisomerase Inhibitors Targeting Gram-Positive and Gram-Negative Pathogens.

Bacterial resistance is increasing rapidly, requiring urgent identification of new antibacterial drugs that are effective against multidrug-resistant pathogens. Novel bacterial topoisomerase inhibitors (NBTIs) provide a new strategy for investigating the well-validated DNA gyrase and topoisomerase IV targets while preventing cross-resistance issues. On this basis, starting from a virtual screening campaign and subsequent structure-based hit optimization guided by X-ray studies, a novel class of piperazine-like NBTIs with outstanding enzymatic activity against and DNA gyrase and topoisomerase IV was identified.

Molecular basis for the different interactions of congeneric substrates with the polyspecific transporter AcrB.

The drug/proton antiporter AcrB, which is part of the major efflux pump AcrABZ-TolC in Escherichia coli, is the paradigm transporter of the resistance-nodulation-cell division (RND) superfamily. Despite the impressive ability of AcrB to transport many chemically unrelated compounds, only a few of these ligands have been co-crystallized with the protein. Therefore, the molecular features that distinguish good substrates of the pump from poor ones have remained poorly understood to date.

A New Acid-oxidizing Solution: Assessment of Its Role on Methicillin-resistant Staphylococcus aureus (MRSA) Biofilm Morphological Changes.

Objective: Biofilms represent a key challenge in the treatment of chronic wounds, as they are among the main reasons for delays in chronic wound healing. This in vitro study was aimed at evaluating the activity of a new acid-oxidizing solution (AOS) on biofilm formation. Acid-oxidizing solution contains free chlorine species with stabilized hypochlorous acid in high concentration (> 95%) and is characterized by acidic (pH less than 3) and super-oxidizing (Redox greater than 1000mV) features.