Integron-mediated multidrug resistance in a global collection of nontyphoidal Salmonella enterica isolates.
Salmonella enterica bacteria have become increasingly resistant to antimicrobial agents, partly as a result of genes carried on integrons. Clonal expansion and horizontal gene transfer may contribute to the spread of antimicrobial drug-resistance integrons in these organisms. We investigated this resistance and integron carriage among 90 isolates with the ACSSuT phenotype (resistance to ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, and tetracycline) in a global collection of S. enterica isolates. Four integrons, dfrA12/orfF/aadA2, dfrA1/aadA1, dfrA7, and arr2/blaOXA30/cmlA5/aadA2, were found in genetically unrelated isolates from 8 countries on 4 continents, which supports a role for horizontal gene transfer in the global dissemination of S. enterica multidrug resistance. Serovar Typhimurium isolates containing identical integrons with the gene cassettes blaPSE1 and aadA2 were found in 4 countries on 3 continents, which supports the role of clonal expansion. This study demonstrates that clonal expansion and horizontal gene transfer contribute to the global dissemination of antimicrobial drug resistance in S. enterica.
Krauland
Mary G
MG
Infectious Diseases Epidemiology Research Unit, University of Pittsburgh School of Medicine and Graduate School of Public Health, Pittsburgh, Pennsylvania 15261, USA.
Marsh
Jane W
JW
Paterson
David L
DL
Harrison
Lee H
LH
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D022761:Gene Transfer, Horizontal; D014943:Global Health; D006801:Humans; D032023:Integrons / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction; D012480:Salmonella Infections / Q000382:microbiology / Q000635:transmission; D019779:Salmonella enterica / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D012486:Salmonella typhimurium / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification; D017422:Sequence Analysis, DNA; D012703:Serotyping
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins