Penicillin-binding proteins in Listeria monocytogenes

Area of Science:

• Microbiology
• Molecular Biology
• Biochemistry

Background:

• Listeria monocytogenes is a significant foodborne pathogen.
• Understanding antibiotic targets like penicillin-binding proteins (PBPs) is crucial for combating bacterial infections.
• Bacterial tolerance to antibiotics can arise from alterations in PBP function or expression.

Purpose of the Study:

• To characterize the penicillin-binding proteins (PBPs) in Listeria monocytogenes ATCC 15313.
• To investigate the effects of Dicloxacillin and Penicillin G on the morphology of Listeria monocytogenes.

Main Methods:

• Utilized 125I-Penicillin X as a radiotracer to identify and quantify PBPs.
• Membrane protein isolation and analysis.
• Morphological assessment of bacterial cells under antibiotic stress.

Main Results:

• Identified at least five distinct PBPs in Listeria monocytogenes membranes with varying affinities for radiolabeled penicillin and Dicloxacillin.
• Estimated molecular weights of the identified PBPs were 76, 74, 67, 66, and 47 KDa.
• Sub-inhibitory concentrations of Dicloxacillin induced filamentation in Listeria monocytogenes, whereas Penicillin G did not alter cell morphology.

Conclusions:

• Listeria monocytogenes possesses multiple PBPs that can bind penicillin derivatives.
• Dicloxacillin exhibits distinct morphological effects compared to Penicillin G, suggesting differential interaction with bacterial targets or pathways.
• These findings contribute to understanding the mechanisms of antibiotic tolerance and resistance in Listeria monocytogenes.