Novel Design of High Affinity Beta‐Lactamase Inhibitors

Resistance to antibiotics is a major public health care concern. Most of the broad spectrum antibiotics such as penicillin's, could be inactivated in the presence of bacterial beta‐lactamases that hydrolyse the beta‐lactam ring of antibiotics resulting in the loss of antibacterial properties. Thus, blocking bacterial beta‐lactamase activity will overcome bacteria resistance to antibiotics. To develop new beta‐lactamase inhibitors we employed aptamer technology and performed SELEX enrichment of ssDNA aptamers for beta‐lactamases. Among the beta‐lactamases, CTX and KPC show the highest resistance not only to the broad spectrum antibiotics but also the newer cephalosporins and carbpenemases, and thus they were used as the targets. The SELEX was carried out using random ssDNA library with 10 14 –10 15 unique sequences and the aptamers were enriched based on the affinity towards the beta‐lactamases. This was followed by a functional selection wherein we partitioned the progressive pools based on their inhibitory activity visualized by a Nitrocefin assay. This led us to an aptamer pool with high affinity and inhibitory activity against CTX and KPC. The obtained aptamer pool will be sequenced and the dominant sequences will be synthesized and further validated for their inhibitory capacity against various beta‐lactamases. This study opens a new direction for antibiotics development by using aptamer technology.