Repositioning of Benzodiazepine Drugs and Synergistic Effect with Ciprofloxacin Against ESKAPE Pathogens.

Infectious diseases are among the leading causes of morbidity and mortality worldwide. Combating them becomes more complex when caused by the pathogens of the ESKAPE group, which are Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp. The purpose of this study was to investigate the repositioning potential of the benzodiazepines clonazepam and diazepam individually and in combination with the antibacterial ciprofloxacin against ESKAPE. The minimum inhibitory concentration and minimum bactericidal concentration against seven American Type Culture Collection (ATCC) reference standard strains and 64 ESKAPE clinical isolates were determined. In addition, the interaction with ciprofloxacin was determined by the checkerboard method and fractional inhibitory concentration index (FICI) of clonazepam against 11 ESKAPE and diazepam against five ESKAPE. We also list the results found and their clinical significance. Benzodiazepines showed similar antibacterial activity against Gram-positive and Gram-negative. The checkerboard and FICI results showed a synergistic effect of these drugs when associated with ciprofloxacin against almost all tested isolates. Viewing the clinical cases studied, benzodiazepines have potential as treatment alternatives. The results allow us to conclude that clonazepam and diazepam, when in combination with ciprofloxacin, have promising activity against ESKAPE, therefore, assuming the position of candidates for repositioning.

Repositioning of antidepressant drugs and synergistic effect with ciprofloxacin against multidrug-resistant bacteria.

The repositioning of drugs has been shown to be an advantageous alternative for treating diseases caused by multidrug-resistant (MDR) microorganisms. The study aimed to investigate the in vitro antibacterial activity of the antidepressants fluoxetine and paroxetine alone and in combination with the antibacterial ciprofloxacin against standard strains and clinical isolates to explore the repositioning of these drugs in severe bacterial infections. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), tolerance level, fractional inhibitory concentration index (FICI) and interaction of antidepressants with the ciprofloxacin antibiotic were determined using the Checkerboard method against six American Type Culture Collection (ATCC) standard strains and seventy MDR clinical isolates. Both antidepressants showed better antibacterial activity than ciprofloxacin, in addition to being separately bactericidal against all tested Gram-negative and Gram-positive strains. When associated with ciprofloxacin, fluoxetine and paroxetine exhibited significant synergism compared to seventy ciprofloxacin-resistant clinical isolates, demonstrating that these antidepressants were able to increase the antibacterial activity of the antibiotic by eight times. The combination of antidepressants with ciprofloxacin showed relatively better activity against Acinetobacter baumannii, Enterococcus faecium and Klebsiella pneumoniae, strains in which the FICI value obtained was 0.008. The MDR isolates tested in this study ratify the antibacterial properties of the non-antibiotic fluoxetine and paroxetine. In addition, synergism when associated with ciprofloxacin is an alternative for treating serious infections in hospitalized patients. However, additional in vivo studies must be conducted to elucidate the mechanisms of action of these drugs.

Crystal structure of 7-[(2E)-2-benzyl-idene-3-oxobut-oxy]-4-methyl-2H-chromen-2-one.

Two independent mol-ecules (A and B) comprise the asymmetric unit of the title compound, C21H18O4. There are significant conformational differences between the mol-ecules relating in particular to the relative orientation of the 3-oxo-2-(phenyl-methyl-idene)but-oxy substituent with respect to the superimposable chromen-2-one residues. To a first approximation, the substituents are mirror images; both are approximately perpendicular to the chromen-2-one fused ring system with dihedral angles of 88.50 (7) (A) and 81.96 (7)° (B). Another difference between the independent mol-ecules is noted in the dihedral angles between the adjacent phenyl and but-3-en-2-one groups of 8.72 (12) (A) and 27.70 (10)° (B). The conformation about the ethene bond in both mol-ecules is E. The crystal packing features C-H⋯O, C-H⋯π(ar-yl) and π-π [Cg⋯Cg = 3.6657 (8) and 3.7778 (8) Å] stacking inter-actions, which generate a three-dimensional network.

Crystal structure of (3E)-3-[(4-nitro-phen-oxy)-meth-yl]-4-phenyl-but-3-en-2-one.

In the title compound, C17H15NO4, the conformation about the C=C double bond [1.348 (2) Å] is E with the ketone group almost co-planar [C-C-C-C torsion angle = 7.2 (2)°] but the phenyl group twisted away [C-C-C-C = 160.93 (17)°]. The terminal aromatic rings are almost perpendicular to each other [dihedral angle = 81.61 (9)°] giving the mol-ecule an overall U-shape. The crystal packing feature benzene-C-H⋯O(ketone) contacts that lead to supra-molecular helical chains along the b axis. These are connected by π-π inter-actions between benzene and phenyl rings [inter-centroid distance = 3.6648 (14) Å], resulting in the formation of a supra-molecular layer in the bc plane.

Crystal structure of (3E)-3-(2,4-di-nitro-phen-oxy-meth-yl)-4-phenyl-but-3-en-2-one.

In the title compound, C17H14N2O6, the conformation about the C=C double bond [1.345 (2) Å] is E, with the ketone moiety almost coplanar [C-C-C-C torsion angle = 9.5 (2)°] along with the phenyl ring [C-C-C-C = 5.9 (2)°]. The aromatic rings are almost perpendicular to each other [dihedral angle = 86.66 (7)°]. The 4-nitro moiety is approximately coplanar with the benzene ring to which it is attached [O-N-C-C = 4.2 (2)°], whereas the one in the ortho position is twisted [O-N-C-C = 138.28 (13)°]. The mol-ecules associate via C-H⋯O inter-actions, involving both O atoms from the 2-nitro group, to form a helical supra-molecular chain along [010]. Nitro-nitro N⋯O inter-actions [2.8461 (19) Å] connect the chains into layers that stack along [001].

Ethyl (2Z)-3-oxo-2-(3,4,5-tri-meth-oxy-benzyl-idene)butano-ate.

In the title compound, C16H20O6, the conformation about the C=C double bond [1.344 (2) Å] is Z. With respect to this bond, the ketone is almost coplanar [C-C-C-O torsion angle = -179.60 (10)°] and the ester is almost perpendicular [C-C-C-O = 78.42 (13)°]. The meth-oxy substituents of the central benzene ring are either almost coplanar [C-C-O-C = 3.54 (15) and 177.70 (9)°] or perpendicular [C-C-O-C = 80.08 12)° for the central substituent]. In the crystal, the three-dimensional architecture features C-H⋯O and π-π [inter-centroid distance = 3.6283 (6) Å] inter-actions.

Ethyl (2E)-2-(2H-1,3-benzodioxol-5-yl-methyl-idene)-4-chloro-3-oxobutano-ate.

In the title compound, C(14)H(13)ClO(5), the five-membered ring is in an envelope conformation with the methyl-ene C-atom being the flap. The conformation about the C=C double bond [1.341 (2) Å] is E. The chloro-propan-2-one residue is approximately orthogonal to the remaining mol-ecule [dihedral angle = 88.03 (6)°]. In the crystal, the mol-ecules associate via C-H⋯O inter-actions, involving both carbonyl-O atoms, giving rise to an undulating two-dimensional array in the ac plane.