Inter- and Intraspecies Plasmid-Mediated Transfer of Florfenicol Resistance in Enterobacteriaceae Isolates from Swine

Abstract

Florfenicol resistance was analyzed in 230 enteric pig isolates collected between 1998 and 2006. PCR, plasmid profiling, Southern blot hybridization, and a mixed-broth conjugation assay suggested the intra- and interspecies plasmid-mediated transfer of florfenicol resistance among the isolates that exhibited MICs for florfenicol between 4 to 128 mg/liter.

Antibiotic Resistance Patterns and Detection ofblaDHA-1inSalmonellaSpecies Isolates from Chicken Farms in South Korea

“…Conjugation experiments demonstrated the transfer of cefoxitin resistance from six DHA-1-positive isolates (E. coli and K. pneumoniae isolated from swine [20] and S. Montevideo [9], one K. pneumoniae [1025; KTCC], and two S. Indiana isolates) identified in this study. However, cefoxitin resistance was not transferred by one K. pneumoniae isolate (10255; KTCC) and one S. Indiana isolate (MIC, 2 g/ml).…”

“…Lee (9), single samples of E. coli and K. pneumoniae isolated from swine (20), and two K. pneumoniae clinical isolates (10252 and 10255) obtained from the Korean Type Culture Collection (KTCC), all of which contain the DHA-1 gene, were also included in this study.…”

“…Mixed broth culture mating was performed as described previously with E. coli J53AzR (resistant to azide) as a recipient strain to observe the transferability of cefoxitin resistance (20). Briefly, a single colony of the donor and recipient strains grown in TSB were mixed and incubated at 37°C for 20 h. MacConkey agar supplemented with sodium azide (200 g/ml) and cefoxitin (2 g/ml) was used to select for transconjugants.…”

Solution structure and small angle scattering analysis of TraI (381–569)

“…This process of DNA transfer, first observed almost 60 years ago, is a major mechanism by which diverse species of bacteria acquire both antibacterial resistance and metabolic cassettes, and it is a driving force of bacterial evolution 4–7. Conjugation is common in the bacterial world, occurring between different bacterial species and even reported to occur between bacterial and human cells 7–13. The prospects of manipulating horizontal gene transfer to curtail the spread of antibacterial resistance, and more broadly to understand bacterial evolution, are predicated in part on a detailed understanding of the molecular mechanism of this process.…”

Plasmid Typing and Resistance Profiling of Escherichia fergusonii and Other Enterobacteriaceae Isolates from South Korean Farm Animals

“…Mixed broth culture mating was performed with the azide-resistant E. coli J53AzR strain as a recipient for all ampicillin-resistant E. fergusonii isolates. Similar conjugation ex-periments were also performed for four E. coli isolates from cattle and pigs kindly provided by S. K. Lim from NVRQS (15), single isolates of E. coli and K. pneumoniae from swine from our previous research work (20), a Salmonella enterica serovar Montevideo clinical isolate kindly provided by lebsiella J. Y. Kim (12), three Salmonella enterica serovar Indiana poultry isolates from recent research work (19), and two K. pneumoniae clinical isolates (10252 and 10255) obtained from the Korean Type Culture Collection (KTCC) (18) to determine if the E. fergusonii isolates contained similar transferable genetic factors to these other pathogens.…”