New Antimicrobial Strategies to Treat Multi-Drug Resistant Infections Caused by Gram-Negatives in Cystic Fibrosis.

People with cystic fibrosis (CF) suffer from recurrent bacterial infections which induce inflammation, lung tissue damage and failure of the respiratory system. Prolonged exposure to combinatorial antibiotic therapies triggers the appearance of multi-drug resistant (MDR) bacteria. The development of alternative antimicrobial strategies may provide a way to mitigate antimicrobial resistance. Here we discuss different alternative approaches to the use of classic antibiotics: anti-virulence and anti-biofilm compounds which exert a low selective pressure; phage therapies that represent an alternative strategy with a high therapeutic potential; new methods helping antibiotics activity such as adjuvants; and antimicrobial peptides and nanoparticle formulations. Their mechanisms and in vitro and in vivo efficacy are described, in order to figure out a complete landscape of new alternative approaches to fight MDR Gram-negative CF pathogens.

Characterization of the dispirotripiperazine derivative PDSTP as antibiotic adjuvant and antivirulence compound against Pseudomonas aeruginosa.

Pseudomonas aeruginosa is a major human pathogen, able to establish difficult-to-treat infections in immunocompromised and people with cystic fibrosis (CF). The high rate of antibiotic treatment failure is due to its notorious drug resistance, often mediated by the formation of persistent biofilms. Alternative strategies, capable of overcoming P. aeruginosa resistance, include antivirulence compounds which impair bacterial pathogenesis without exerting a strong selective pressure, and the use of antimicrobial adjuvants that can resensitize drug-resistant bacteria to specific antibiotics. In this work, the dispirotripiperazine derivative PDSTP, already studied as antiviral, was characterized for its activity against P. aeruginosa adhesion to epithelial cells, its antibiotic adjuvant ability and its biofilm inhibitory potential. PDSTP was effective in impairing the adhesion of P. aeruginosa to various immortalized cell lines. Moreover, the combination of clinically relevant antibiotics with the compound led to a remarkable enhancement of the antibiotic efficacy towards multidrug-resistant CF clinical strains. PDSTP-ceftazidime combination maintained its efficacy in vivo in a Galleria mellonella infection model. Finally, the compound showed a promising biofilm inhibitory activity at low concentrations when tested both in vitro and using an ex vivo pig lung model. Altogether, these results validate PDSTP as a promising compound, combining the ability to decrease P. aeruginosa virulence by impairing its adhesion and biofilm formation, with the capability to increase antibiotic efficacy against antibiotic resistant strains.

The novel drug candidate VOMG kills Mycobacterium abscessus and other pathogens by inhibiting cell division.

AIMS: The incidence of lung infections is increasing worldwide in individuals suffering from cystic fibrosis and chronic obstructive pulmonary diseases. Mycobacterium abscessus is associated to chronic lung deterioration in these populations. The intrinsic resistance of M. abscessus to most conventional antibiotics jeopardizes treatment success rates. To date no single drug has been developed targeting specifically M. abscessus. Our objective was to characterize the pyrithione-core drug-like small molecule named VOMG as a new compound active against M. abscessus and other pathogens. METHODS: We used a multidisciplinary approach including microbiological, chemical, biochemical and transcriptomics procedures to validate VOMG as a promising anti-M. abscessus drug candidate. RESULTS: We report for the first time the in vitro and in vivo bactericidal activity of VOMG against M. abscessus and other pathogens. Besides being active against M. abscessus biofilm, the compound showed a favourable pharmacology (ADME-Tox) profile. Frequency of resistance studies were unable to isolate resistant mutants. VOMG inhibits cell division, particularly the FtsZ enzyme. CONCLUSIONS: VOMG is a new drug-like molecule discovered against M. abscessus inhibiting cell division with broad spectrum activity against other microbial pathogens.