Genetic and molecular characterization of conjugative R plasmids detected in Salmonella strains isolated from humans and feral pigeons in the same district.

Publisher Website
Google Scholar
Abstract
A total of 24 conjugative R plasmids were isolated from 19 S. typhimurium strains from human patients with acute diarrhea in Hiroshima City [Japan]. There were 6 R plasmids detected in 4 S. typhimurium strains and 1 S. litchfield strain isolated from pigeon droppings collected at 3 parks of the city. Genetic properties of these R plasmids were used as an epidemiologic marker to confirm the possibility of transmission of Salmonella between pigeons and humans. Incompatibility (Inc) group H1 (12 plasmids, 50.0%) was most frequently detected among the 24 human plasmids, followed by IncI.alpha. (4-16.7%) and FII (1-4.2%). Of the 6 plasmids of pigeon origin, 3 were classified into IncI.alpha. and 1 into H1. IncI.alpha. plasmids conferring resistance to streptomycin (Sm), sulfadimethoxine (Su) and tetracycline (Tc) with or without Hg resistance and IncH1 plasmids conferring resistance to chloramphenicol, kanamycin, Sm, Su and Tc with or without Hg resistance were detected in Salmonella strains of both human and pigeon origins. Half of the IncI.alpha. plasmids and all of the H1 plasmids described above were derived from parent S. typhimurium subserovar copenhagen strains with the same biovar, respectively. Five IncI.alpha. and 2 IncH1 R plasmids of human and pigeon origins were .apprx. 76.9 and 120 megadaltons in size, respectively, and the plasmid DNA of each Inc group showed identical restriction pattern. On the basis of the distribution of the same R plasmids in Salmonella strains from humans and pigeons, the possibility of association of pigeons with human salmonellosis was presumed.