A genetic locus involved in iron utilization unique to some Campylobacter strains

Area of Science:

• Microbiology
• Bacterial Genetics
• Iron Metabolism

Background:

• Iron is essential for bacterial growth and virulence.
• Campylobacter species are important foodborne pathogens.
• Mechanisms of iron acquisition in Campylobacter coli are not fully understood.

Purpose of the Study:

• To characterize two genes, cfrA and tonB, involved in iron utilization in Campylobacter coli VC167 T1.
• To investigate the role of these genes in iron uptake and outer membrane protein synthesis.
• To determine the distribution of these genes in different Campylobacter strains.

Main Methods:

• Gene characterization of cfrA and an adjacent TonB-like gene.
• Construction and analysis of site-specific mutants.
• Analysis of iron-repressible outer membrane proteins.
• Hybridization studies using cfrA and tonB gene probes.

Main Results:

• The cfrA gene encodes a putative siderophore receptor involved in iron uptake.
• Mutants defective in cfrA showed reduced synthesis of a major iron-repressible outer membrane protein.
• Mutants in the adjacent TonB-like gene lost the ability to utilize hemin, ferrichrome, and enterochelin.
• The cfrA and tonB genes were present in C. coli and most C. jejuni strains, but absent in some C. jejuni strains.

Conclusions:

• The characterized cfrA and tonB genes play critical roles in iron acquisition in Campylobacter coli.
• These genes are potential markers for differentiating thermophilic Campylobacter species.
• Understanding these iron utilization pathways can inform strategies against Campylobacter infections.