|Vadheim, Virsten - FOOD & DRUG ADM|
Submitted to: Cold Spring Harbor Press
Publication Type: Abstract Only
Publication Acceptance Date: October 12, 1995
Publication Date: N/A
Technical Abstract: Salmonella typhimurium and Brucella abortus are both facultative intracellular parasites of macrophages. The phoP/phoQ regulon has been shown to be essential for full virulence of S. typhimurium. We recently cloned a homolog of the phoP/phoQ regulon from B. abortus 2308, and now have constructed a phoP/phoQ mutant of B. abortus 2308. (B. abortus 2308 is a commonly used challenge strain to test efficacy of bovine brucellosis vaccines.) Survival of B. abortus 2308 and of the B. abortus 2308 phoP/phoQ deletion/replacement mutant in J774 cells (murine cells which have macrophage markers) were similar. The effect of antimicrobial agents was determined on B. abortus strains including vaccine strains. S. typhimurium strains were used with internal controls, so that direct comparisons could be made between B. abortus and S. typhimurium. S. typhimurium was incubated from 30-60 min, and B. abortus was incubated for 3 hrs in the antimicrobial agents, magainin 2, cecropin, mastoporan, and melittin and colony forming units were determined. B. abortus was found to be significantly more resistant to the antimicrobial agents used than S. typhimurium. The B. abortus phoP/phoQ deletion/replacement mutation did not affect the viability of B. abortus 2308 to the antimicrobial agents.