Characterizing arginine, ornithine, and putrescine pathways in enteric pathobionts

Area of Science:

• Microbiology
• Metabolomics
• Bacterial Physiology

Background:

• Arginine-ornithine metabolism is vital for bacterial homeostasis.
• Metabolic pathways and products of arginine are not fully understood in many gut bacteria.

Purpose of the Study:

• To elucidate arginine utilization and downstream metabolic products in enteric pathobionts.
• To identify key enzymes and pathways involved in arginine metabolism.

Main Methods:

• Genomic screening to identify metabolic targets.
• Liquid chromatography-tandem mass spectrometry (LC-MS/MS) for targeted metabolomics.
• Analysis of cell-free conditioned media from nine enteric pathobionts.

Main Results:

• All tested bacteria consumed glutamine, glutamate, and arginine, producing citrulline, ornithine, and GABA.
• E. coli, K. pneumoniae, K. aerogenes, and P. fluorescens converted arginine to agmatine and produced putrescine.
• Arginine supplementation enhanced K. pneumoniae biofilm formation; ornithine supplementation enhanced S. epidermidis biofilm formation.

Conclusions:

• Comprehensive insights into arginine-ornithine metabolism in enteric pathobionts were achieved.
• Specific metabolic pathways and their influence on bacterial behavior, such as biofilm formation, were identified.