Antimicrobial activity of cationic carbosilane dendrimers against clinical strains of extended-spectrum beta-lactamase producing-Escherichia coli and their biofilms

<h2>Abstract</h2> Antimicrobial resistance (AMR) is a significance public health concern with serious health and socioeconomic consequences. Therefore, multidrug-resistant strains such as extended-spectrum beta-lactamase (ESBL) producing-Enterobacterales are becoming increasingly common and there are few antibiotic options to treat them. Consequently, it is urgent to find new therapeutic compounds, and cationic dendrimers, such as carbosilane (CBS) derivatives, with peripheral ammonium groups are possible candidates for this purpose. The aim of this study was to establish the antimicrobial and biological properties of different cationic CBS dendrimers and dendrons against multiresistant clinical strains of ESBL-producing <i>Escherichia coli</i>. All seven compounds tested were found to be effective <i>in vitro</i> against planktonic forms. The most active compounds inhibited the formation of bacterial biofilms but lacked activity against pre-formed biofilms. These dendrimers differed in their mode of action depending on the structure and the cationic groups, which was analysed by studies with interaction of membrane models. In addition, these four dendritic systems mentioned above showed a good therapeutic margin in the haemolysis assays <i>in vitro</i> and they lacked haemagglutinating properties. In conclusion, some of the compounds tested could be candidates as potential topical antimicrobials or disinfectants against ESBL-producing enterobacteria infections.