Construction and Characterization of an lpxM-Deficient Strain Using a pyrF/5-FOA Counterselection System.

AIM

Multidrug-resistant (MDR-) is on the rise, making it challenging to achieve the desired therapeutic effects with existing conventional antibiotics. The search for new antibacterial targets has emerged as a significant research focus.

PURPOSE

The lysophospholipid acyltransferases (LPLATs) proteins encoded by the lpxM gene play a pivotal role in the biosynthesis of lipopolysaccharides (LPS). LPS is a critical component of the outer membrane of the cell wall and is essential for the survival and drug resistance of Gram-negative bacteria. This study aims to investigate the effects of the lpxM gene on the growth and drug susceptibility of MDR-.

METHODS

The standard strain of () s selected as the target. The lpxM gene was knocked out using the pyrF/5-FOA-based counterselectable method. Subsequently, the growth status and the minimum inhibitory concentration (MIC) of the knockout strain against conventional antibiotics were compared.

RESULTS

The lpxM gene in AYE was successfully and fully knocked out. The absorbance value at OD600 for the lpxM knockout strain during the stable period was observed to be as low as 2.5, indicating a significant reduction in growth rate. Furthermore, the MIC of the knockout strain for imipenem decreased from 16 μg/mL to 1 μg/mL, and the MIC for ceftazidime decreased from 32 μg/mL to 16 μg/mL, enhancing antibiotic sensitivity.

CONCLUSION

This study demonstrates that the deletion of the lpxM gene induces alterations in the growth and drug resistance of , providing a crucial foundation for further investigation into the mechanisms underlying LPS-mediated drug resistance and for the screening of effective auxiliary inhibitors targeting lpxM against MDR-.