Anti-Campylobacter Activity of Ternary Copper(II) Complexes with Imine Ligands and...

Herein, two Cu-(II) complexes of the type [Cu-(N-N)-(mftpy)]-(PF₆)₂ (N-N = 4-chloro-N-(pyridin-2-methylene) aniline (Clmp) or 4-methyl-N-(pyridin-2-methylene) aniline (memp)-and mftpy = 4'-(4-methylphenyl)-2,2':6',2″-terpyridine) were successfully synthesized and characterized by microanalysis (% CHN), high-resolution mass spectrometry, Fourier-transform infrared spectroscopy, and ultraviolet-visible (solution and solid state) and electron paramagnetic resonance spectroscopies (solution and solid state). Next, the in vitro antibacterial activity of the [Cu-(Clmp)-(mftpy)]-(PF₆)₂ CL1 and [Cu-(memp)-(mftpy)]-(PF₆)₂ CL2 complexes was investigated in the planktonic and sessile form of Campylobacter jejuni and Campylobacter coli strains selected from a bank of strains characterized by resistance to first-line antibiotics. The quantification of planktonic cells showed a reduction that varied from 1.3 to 6.9 log CFU (colony forming units)/mL at a minimum inhibitory concentration of 25-400 μg/mL according to the tested strain. The biofilms suffered modification in their ultrastructure and showed evidence of the action of both complexes that surpassed the results with peracetic acid, with a reduction ≥2.6 log CFU/mL of sessile Campylobacter, with control of 1.2 orders of magnitude in the biomass formation by CL2, and the highest penetration (4.92 μg) of CL1 into the C. jejuni biofilm. The results identified show that both complexes are biologically active, activating processes that allow the control of the pathogen in both lifestyles.