title: Comparison of virulence factors and R plasmids of Salmonella spp. isolated from healthy and ill swine.
abstract: The antibiotic resistance and virulence profiles of Salmonella spp. isolated from healthy (group 1) and ill (group 2) swine were compared. Parameters studied included colicin and siderophore production; mannose-sensitive hemagglutination of erythrocytes; resistance to the lethal effect of serum complement; resistance to antibiotics; and the transmissibility of these characteristics to recipient organisms. Group 1 (19 isolates) had 14 serotypes, and group 2 (20 isolates) had 2 serotypes. Isolates from group 2 were resistant to more antibiotics and had a greater ability to hemagglutinate erythrocytes and transfer R plasmids to recipient organisms, but a lesser ability to produce siderophore than group 1. All 39 isolates resisted the lethal effects of serum complement. Colicin was produced by 1 of 19 from group 1 and 0 of 20 from group 2. A donor Escherichia coli isolated from a pig with enteritis transferred R plasmids to 62% of group 1 and 0% of group 2 Salmonella spp. when they were used as recipient organisms. A transconjugant from the mating of donor E. coli to a group 1 Salmonella spp. was further able to pass an R plasmid to recipient E. coli and salmonellae. Plasmid isolation from group 1 yielded 1 of 19 strains with a 56-megadalton plasmid, while 20 of 20 strains from group 2 contained three to five plasmids from 2.4 to 60 megadaltons in size.
authors.affiliation: Department of Medical Microbiology, College of Veterinary Medicine, University of Georgia, Athens 30602.
authors.forename: K W
authors.initials: KW
authors.lastname: Simmons
authors.forename: R E
authors.initials: RE
authors.lastname: Wooley
authors.forename: J
authors.initials: J
authors.lastname: Brown
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001770:Blood Bactericidal Activity; D003087:Colicins / Q000096:biosynthesis; D003165:Complement System Proteins / Q000276:immunology; D003227:Conjugation, Genetic; D004269:DNA, Bacterial / Q000032:analysis; D004196:Disease Outbreaks / Q000662:veterinary; D004758:Enterobactin / Q000096:biosynthesis; D006386:Hemagglutination Tests; D011815:R Factors; D012475:Salmonella / Q000145:classification / Q000187:drug effects / Q000235:genetics / Q000472:pathogenicity*; D012481:Salmonella Infections, Animal / Q000382:microbiology*; D012703:Serotyping; D013552:Swine / Q000382:microbiology*; D013553:Swine Diseases / Q000382:microbiology*; D014774:Virulence
chemical_list: D000900:Anti-Bacterial Agents; D003087:Colicins; D004269:DNA, Bacterial; D004758:Enterobactin; D003165:Complement System Proteins