The effect of novel β-lactam derivatives synthesized from substituted phenethylamines on resistance genes of MRSA isolates.

This study focuses on the activity of previously reported imine and β-lactam derivatives against methicillin-resistant Staphylococcus aureus (MRSA) isolates. The presence of mecA and blaZ genes in the isolates was determined, and the minimum inhibitory concentration (MIC) values were determined based on the antibacterial activity against these isolates. Active compounds were selected and their ability to act against resistant isolates in vitro was determined. Concurrently, biochemical (nitrocefin) and molecular (qRT-PCR) tests were used to investigate the ability of the compounds to induce resistance genes in MRSA isolates. The cytotoxicity of the compounds on human dermal fibroblasts (HDF) was investigated. The MIC values of compounds (10) and (12) against MSSA and MRSA isolates were 7.81 and 15.62 μg ml, respectively. The most active compounds were identified as (10) and (12), and it was observed that the isolates did not develop resistance to these compounds in vitro. These compounds were found to inhibit β-lactamase, reduce the expression of resistance genes, and exhibit reduced HDF cell toxicity in a dose-dependent manner. According to the findings of the study, it can be concluded that these compounds show promise as hits with an interesting mechanism of action for further chemical modifications to develop new MRSA inhibitors.