Antibacterial and antibiofilm activity of 1-thiocarbamoyl-3,5-diaryl-4,5-dihydro-1H pyrazoles and thiazoles in multidrug-resistant pathogens.

To find novel antibiotic drugs, six 1-thiocarbamoyl-3,5-diaryl-4,5-dihydro-1H derivatives named 1b, 1d (pyrazoles), 2a, 2b, 2c, and 2d (thiazoles) were evaluated in silico and in vitro. The in silico analyses were based on ADME pharmacokinetic parameters (absorption, distribution, metabolism, and excretion). The in vitro antibacterial activity was evaluated in Gram-positive and Gram-negative species (Staphylococcus aureus ATCC® 25904, Staphylococcus epidermidis ATCC® 35984, Klebsiella pneumoniae ATCC® 700603, and Acinetobacter baumannii ATCC® 19606), by determination of minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC), kinetics curve, and antibiofilm assays. As results, the azoles have activity against the Gram-negative species K. pneumoniae ATCC® 700603 and A. baumannii ATCC® 19606. No antibacterial activity was observed for the Gram-positive bacteria evaluated. Thus, the azoles were evaluated against clinical isolates of K. pneumoniae carbapenemase (KPC) and A. baumannii multidrug-resistant (Ab-MDR). All azoles have antibacterial activity against Ab-MDR isolates (Gram-negative) with MIC values between 512 μg/mL and 1,024 μg/mL. Against KPC isolates the azoles 1b, 1d, and 2d present antibacterial activity (MIC = 1,024 μg/mL). In the kinetics curve assay, the 1b and 1d pyrazoles reduced significantly viable cells of Ab-MDR isolates and additionally inhibited 86.6 to 95.8% of the biofilm formation. The in silico results indicate high possibility to permeate the blood-brain barrier (2b) and was predict human gastrointestinal absorption (all evaluated azoles). Considering that the research and development of new antibiotics is a priority for drug-resistant pathogens, our study revealed the antibacterial and antibiofilm activity of novel azoles against K. pneumoniae and A. baumannii pathogens.