Effects of benzydamine and mouthwashes containing benzydamine on Candida albicans adhesion, biofilm formation, regrowth, and persistence.

OBJECTIVES: To assess the effects of benzydamine and mouthwashes (MoWs) containing benzydamine on different stages of Candida albicans biofilm: adhesion, formation, persistence, and regrowth (if perturbed). MATERIALS AND METHODS: C. albicans CA1398, carrying the bioluminescence ACT1p-gLUC59 fusion product, was employed. Fungal cells were exposed for 1', 5', or 15' to 4 different benzydamine concentrations (0.075 to 0.6%) to 2 mouthwashes (MoWs) containing benzydamine and to a placebo MoW (without benzydamine). Treated cells were tested for adhesion (90 min) and biofilm formation (24-h assay). Next, 24- and 48-h-old biofilms were exposed to benzydamine and MoWs to assess regrowth and persistence, respectively. The effects of benzydamine, MoWs containing benzydamine, and placebo on different biofilm stages were quantified by bioluminescence assay and by the production of quorum sensing (QS) molecules. RESULTS: Benzydamine and MoWs containing benzydamine impaired C. albicans ability to adhere and form biofilm, counteracted C. albicans persistence and regrowth, and impaired a 48-h-old biofilm. Some of these effects paralleled with alterations in QS molecule secretion. CONCLUSIONS: Our results show for the first time that benzydamine and MoWs containing benzydamine impair C. albicans capacity to form biofilm and counteract biofilm persistence and regrowth. CLINICAL RELEVANCE: Benzydamine and MoWs containing benzydamine capacity to affect C. albicans biofilm provides an interesting tool to prevent and treat oral candidiasis. Likely, restraining C. albicans colonization through daily oral hygiene may counteract colonization and persistence by other critical oral pathogens, such as Streptococcus mutans, whose increased virulence has been linked to the presence of C. albicans biofilm.

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. The activity of the compounds against clinical multidrug-resistant isolates of S. aureus, Clostridium difficile, Acinetobacter baumannii, Neisseria gonorrhoeae, E. coli and vancomycin-resistant Enterococcus spp. was also confirmed. Two compounds (1 and 2) were tested in time-kill and post-antibiotic effect (PAE) assays. Compound 1 was bactericidal against all tested reference strains and showed higher activity than ciprofloxacin, and compound 2 showed a prolonged PAE, even against the ciprofloxacin-resistant S. aureus BAA-1720 strain. Spontaneous development of resistance to both compounds was selected for in S. aureus at frequencies comparable to those obtained for quinolones and other NBTIs. S. aureus BAA-1720 mutants resistant to compounds 1 and 2 had single point mutations in gyrA or gyrB outside of the quinolone resistance-determining region (QRDR), confirming the distinct site of action of these NBTIs compared to that of quinolones. Overall, the very good antibacterial activity of the compounds and their optimizable in vitro safety and physicochemical profile may have relevant implications for the development of new broad-spectrum antibiotics.

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. MATERIALS AND METHODS: A 3-dimensional in vitro model of reconstructed human epidermis was used to compare the activity of AOS vs 2 reference products (RP) containing betaine and polyhexanide (RP1) and sodium hypochlorite and hypochlorous acid (RP2). Different approaches were used to assess the prevention and eradication of methicillin-resistant Staphyloccocus aureus biofilm by the study products. Xylitol and chlorhexidine were used as positive controls. The activity of the study products on the biofilm structure was evaluated analyzing the ultrastructural modification by scanning electron microscopy, while skin compatibility was assessed on noncolonized tissues measuring the metabolic activity of the cells. RESULTS: In all experiments, AOS showed to be active on the biofilm matrix, modifying its structure and allowing bacterial release from the matrix. In all experiments, no cytotoxicity was observed in the tissues treated with the product suggesting a good compatibility of AOS with skin tissues. Reference product 1 affected the biofilm, suggesting a disruption effect; RP2 was slightly less active than AOS in modifying the biofilm structure. CONCLUSION: Treatment with AOS affects biofilm by modifying its structure and therefore facilitating local bacteria accessibility to bactericidal agents, with consequent potential clinical benefits in the treatment of chronic wounds.

Discovery and pharmacological profile of new 1H-indazole-3-carboxamide and 2H-pyrrolo[3,4-c]quinoline derivatives as selective serotonin 4 receptor ligands.

Since the discovery of the serotonin 4 receptor (5-HT(4)R), a large number of receptor ligands have been studied. The safety concerns and the lack of market success of these ligands have mainly been attributed to their lack of selectivity. In this study we describe the discovery of N-[(4-piperidinyl)methyl]-1H-indazole-3-carboxamide and 4-[(4-piperidinyl)methoxy]-2H-pyrrolo[3,4-c]quinoline derivatives as new 5-HT(4)R ligands endowed with high selectivity over the serotonin 2A receptor and human ether-a-go-go-related gene potassium ion channel. Within these series, two molecules (11 ab and 12 g) were identified as potent and selective 5-HT(4)R antagonists with good in vitro pharmacokinetic properties. These compounds were evaluated for their antinociceptive action in two analgesia animal models. 12 g showed a significant antinociceptive effect in both models and is proposed as an interesting lead compound as a 5-HT(4)R antagonist with analgesic action.