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

Area of Science:

• Microbiology
• Molecular Biology
• Drug Discovery

Background:

• Multidrug-resistant Acinetobacter baumannii (MDR-AB) poses a significant threat due to limited effective antibiotic options.
• Lipopolysaccharide (LPS) biosynthesis, involving lysophospholipid acyltransferases (LPLATs) encoded by lpxM, is crucial for Gram-negative bacterial survival and drug resistance.

Purpose of the Study:

• To investigate the impact of the lpxM gene on the growth and drug susceptibility of MDR-AB.
• To explore lpxM as a potential target for novel antibacterial strategies against MDR-AB.

Main Methods:

• Gene knockout of lpxM in Acinetobacter baumannii (AB) AYE using a pyrF/5-FOA-based counterselectable method.
• Comparative analysis of growth rates (OD600) and minimum inhibitory concentrations (MICs) of the lpxM knockout strain against conventional antibiotics.

Main Results:

• Successful and complete knockout of the lpxM gene was achieved.
• The lpxM knockout strain exhibited a significantly reduced growth rate (OD600 ~2.5).
• Antibiotic sensitivity was enhanced, with decreased MICs for imipenem (16 to 1 μg/mL) and ceftazidime (32 to 16 μg/mL).

Conclusions:

• Deletion of the lpxM gene significantly alters the growth and drug resistance profiles of AB.
• These findings provide a basis for understanding LPS-mediated drug resistance mechanisms.
• Targeting lpxM presents a promising strategy for developing auxiliary inhibitors against MDR-AB.