Bacteremia caused by Salmonella enterica serotype Choleraesuis in Taiwan

Since 1995, there has been a steady increase in the number of reported cases of Salmonella enterica serotype Choleraesuis (S. Choleraesuis) sepsis in Taiwan. Representative Taiwanese survey data from 1996 to 2004 revealed that these adult patients with S. Choleraesuis bacteremia presented with primary bacteremia (57%, especially immunocompromised hosts), mycotic aneurysm (16%), and fever (86%) predominantly. S. Choleraesuis septicemia demonstrated a higher invasion index (with secondary involved sites) than other Salmonella spp. In swine experiments, the inoculation dose of 10³ colony forming units S. Choleraesuis was cleared without apparent sequelae. Transmission of specific strains (with mutations of GyrA and parC, subsequently resistance to fluoroquinolones) from swine, and the acquisition of genes (CMY-2, AmpC complex) encoding beta-lactamases (with resistance to extended-spectrum cephalosporins) have been implicated in the evolution of multiresistant phenotypes of S. Choleraesuis. The virulence plasmid of S. Choleraesuis (pSCV), and other genes mediating adhesion to the epithelial cell membrane of the gastrointestinal tract, were considered important pathogenic factors for S. Choleraesuis. Vaccines for domestic animals combined with effective controls on antibiotic use offer the greatest potential to control the increasing impact of S. Choleraesuis on humans.