Modulation of the bacterial defense mechanisms by various chemical structures

Pharmaceutical active compounds (PhACs) have a remarkable successful effect on fighting animal and human diseases induced by bacteria, too. Over the time, PhACs treatments became victims of their own success, so their intensive use corroborated with their misuse resulted in PhACs treatment resistance microorganisms, becoming a serious health hazard and an environmental threat. In this study, we analysed the effect of four distinct pharmaceutical compounds such as quaternary ammonium compounds (benzenthonium chloride), tricyclic compounds (carbamazepine), fluoroquinolone (ciprofloxacin) and a derived compound from pyrimidine (trimethroprim) on five bacterial gram positive and negative strains which are naturally present in the environment. The results pointed out that carbamazepine had a specific inhibitory effect only on Delfia acidovorans and a border line effect on Staphylococcus warneri. On the other side, trimethroprim (80mg/L trimethropim) inhibited the growth of 3 out of 5 bacterial strains, the resistant strains were Citrobacter freundi and Pseudomonas aurantica. Benzenthonium chloride had an overall inhibitory effect with the exception of Staphylococcus warneri. Interestingly, ciprofloxacin had an inhibitory effect on all bacterial strains regardless of the concentration. This study clearly pointed out that various chemical structures affected specific structural and functional biological bacterial components and their presence into environment could create a massive ecological imbalance with direct impact on human health.