16S rRNA gene sequences.

<div><p>As the effectiveness of current treatments against the development of antimicrobial resistance is declining, new strategies are required. A great source of novel secondary metabolites with therapeutics effects are the endophytic bacteria present in medicinal plants. In this study, <i>Klebsiella aerogenes</i> (an endophytic bacteria belonging to the <i>Enterobacteriaceae</i> family) was isolated from <i>Kalanchoe blossfeldiana</i> (a medicinal plant”. The bacterial secondary metabolites were identified using GC-MS techniques. Furthermore, the antibacterial potentials were investigated against multi-drug resistance (MDR) <i>Salmonella typhi</i> and <i>Staphylococcus aureus</i>. The GC-MS chromatogram of <i>K</i>. <i>aerogenes</i> secondary metabolites extract displayed total of 36 compounds. Ethyl acetate extracts of <i>K</i>. <i>aerogenes</i>, showed mean zone of growth inhibition of 15.00 ± 1.00 against <i>S</i>. <i>typhi</i> and 7.00 ± 1.00mm against <i>S</i>. <i>aureus</i>, respectively. The extract demonstrated significant antibacterial effectiveness against <i>S</i>. <i>typhi</i> and moderate antibacterial efficacy against <i>S</i>. <i>aureus</i>, with minimum inhibitory concentration (MIC) values ranging from 0.089 to 0.39 mg/mL. The time-kill kinetics profile of the ethyl acetate extract against <i>S</i>. <i>typhi</i> revealed a decrease in the number of viable cells during the initial 5, 6, and 24 hours. Conversely, there was a sudden increase in viable cells up to 6 hours for <i>S</i>. <i>aureus</i>. The identified secondary metabolite with high percentage than others, benzeneethanamine exhibited favorable interactions (−7.2 kcal/mol) with the penicillin-binding protein (PBP2a) of <i>S</i>. <i>aureus</i> and (−7.5 kcal/mol) osmoporin (OmpC) of <i>S</i>. <i>typhi</i>, indicating its potential as a candidate for drug development against these MDR bacteria. This study reported for the first time, bacterial endophytes associated with <i>K</i>. <i>blossfeldiana</i> with antibacterial activities.</p></div>