Clostridium perfringens urease genes are plasmid borne

Area of Science:

• Microbiology
• Bacterial Pathogenesis
• Molecular Biology

Background:

• Urease activity is common in bacteria and can function as a virulence factor.
• The urease phenotype has not been previously characterized in the anaerobic pathogen Clostridium perfringens.

Purpose of the Study:

• To investigate the presence and characteristics of urease genes (ureABC) in Clostridium perfringens.
• To determine the genetic location and potential co-encoding of urease genes in C. perfringens.

Main Methods:

• Screening of C. perfringens strains for ureABC genes.
• Plasmid analysis to determine gene localization.
• Biochemical characterization and antibody cross-reactivity assays for the urease enzyme.
• Analysis of urease gene regulation under varying nitrogen availability.

Main Results:

• Approximately 2% of C. perfringens strains harbored the ureABC genes.
• These genes were located on large plasmids, often co-encoding toxins (epsilon, iota) or enterotoxin.
• This is the first report of a plasmid-encoded urease in a Gram-positive bacterium.
• The C. perfringens urease showed high similarity to other bacterial ureases and cross-reacted with antibodies against Helicobacter pylori urease.
• Urease production was repressed by urea and induced by nitrogen limitation.

Conclusions:

• Clostridium perfringens possesses plasmid-borne urease genes in a small subset of strains.
• The C. perfringens urease is biochemically similar to ureases from other species.
• Regulation of urease production by nitrogen availability, typically seen with chromosomal genes, is also observed for these plasmid-borne genes.